Dissemination components broadcasts events about member status
updates. When any member attribute is updated (incarnation,
status, UUID, address), the member stands into an event queue.
Members from the queue are encoded into each round step message
with a higher priority and before anti-entropy section.

It means, then even if a cluster consists of hundreds of members
and one of them was updated on one of instances, this update will
be disseminated regardless of whether this memeber is encoded
into anti-entropy section or not. It drastically speeds events
dissemination up, according to the SWIM paper, and is noticed in
the tests.

Part of #3234

Before dissemination component it was enough in the tests to
either drop all packets to/from a certain member, or do not drop
at all. But after dissemination it will be time to test more
granulated packet loss table: not 0/100, but 5/10/20/50/.../100
packet loss rate.

Part of #3234

The test checks that if a member has failed in a big cluster, it
is eventually deleted from all instances. But it takes too much
real time despite usage of virtual time.

This is because member total deletion takes
O(N + ack_timeout * 5) time. N so as to wait until every member
pinged the failed one at least once, + 3 * ack_timeout to learn
that it is dead, and + 2 * ack_timeout to drop it. Of course, it
is an upper border, and usually it is faster but not much. For
example, on the cluster of size 50 it takes easily 55 virtual
seconds.

On the contrary, to just learn that a member is dead on every
instance takes O(log(N)) according to the SWIM paper. On the
same test with 50 instances cluster it takes ~15 virtual seconds
to disseminate 'dead' status of the failed member on every
instance. And even without dissemination component, with
anti-entropy only.

Leaping ahead, for the subsequent patches it is tested that with
the dissemination component it takes already ~6 virtual seconds.

In the summary, without losing test coverage it is much faster to
turn off SWIM GC and wait until the failed member looks dead on
all instances.

Part of #3234

At this moment SWIM protocol stores array of members only in one
place: inside the anti-entropy component. Its decoding is a
simple loop taking the member definitions one by one and
upserting them into the member table.

But the dissemination also has something kinda like members
array: an array of events. The trick is that an event is
basically the same as a member +/- a couple of optional fields.
Events are also decoded into the member definition structure. It
means that anti-entropy decoder can be easily reused.

Part of #3234

Each member stored in components dissemination and anti-entropy
should carry a unique identifier, a status, and an address. Those
attributes are UUID, IP, Port, enum swim_member_status,
incarnation.

Now they are sent only in scope of anti-entropy, but forthcoming
dissemination component also would like to use these attributes
for each event.

This commit makes the vital attributes and their code more
reusable by encapsulation of them into a binary passport
structure.

Part of #3234

Rename vy_set() and vy_set_with_colmask() to vy_tx_set() and
vy_tx_set_with_colmask()

These methods really belong to vy_tx module, so move them there.

Add the type of operation which is being executed to before_replace and
on_replace triggers.

Closes #4099

@TarantoolBot document
Title: new parameter for space before_replace and on_replace triggers
Now before_replace and on_replace triggers accept an additional
parameter: the type of operation that is being executed.
(INSERT/REPLACE/DELETE/UPDATE/UPSERT)
For example, a trigger function may now look like this:
```
function before_replace_trig(old, new, space_name, op_type)
    if op_type == 'INSERT' then
	return old
    else
	return new
    end
end
```
And will restrict all INSERTs, but allow REPLACEs, UPSERTs, DELETEs and
UPDATEs.

Add more logging into wait_fullmesh() and return immediately with false
when 'stopped' status is observed.

The purpose of the change is to provide more information in case of a
master-master replication bootstrap failure.

Apart from speeding up statement comparisons and hence index lookups,
this is also a prerequisite for multikey indexes, which will reuse tuple
comparison hints as offsets in indexed arrays.

Albeit huge, this patch is pretty straightforward - all it does is
replace struct tuple with struct vy_entry (which is tuple + hint pair)
practically everywhere in the code. Now statements are stored and
compared without hints only in a few places, primarily at the very top
level. Hints are also computed at the top level so it should be pretty
easy to replace them with multikey offsets when the time comes.

This patch adds a helper struct vy_entry, which unites a statement with
a hint. We will use this struct to store hinted statements in vinyl data
structures, such as cache or memory tree.

Note, it's defined in a separate file to minimize dependencies.

This patch adds vy_set and vy_set_with_colmask functions. For now they
simply forward all arguments to vy_tx_set, but once comparison hints are
introduced, they will also compute a hint for the inserted statement.
Later, with the appearance of multikey indexes, they will also extract
multikey offsets.

It's a trivial one-line function, which can be folded without hurting
readability, i.e. it only obfuscates the code. Let's kill it.

For aesthetic purposes. No functional changes.

In the next patch I'm planning to introduce the concept of vy_entry,
which will encapsulate a statement stored in a container. Let's rename
vy_cache_entry to vy_cache_node so as not to mix the two concepts.

So as not to include heavy key_def.h when we only need hint_t.

The msgpack dependency has been updated because the new version
introduces the new method mp_stack_top for the mp_stack class
which we will use to store a pointer for a multikey frame to
initialize a field_map in case of multikey index.

As the library API has changed, the code has been modified
correspondingly.

@locker: add missing frame update in vy_stmt_new_surrogate_delete.

Needed for #1012

Improve row printing to log. Since say only has 16k buffer, there is no
point in printing the whole packet, which can have arbitrary length, in one
go.
So, print the header row by row, 16 bytes in a row, and format output to
match `xxd` output:
```
[001] 2019-04-05 18:22:46.679 [11859] iproto V> Got a corrupted row:
[001] 2019-04-05 18:22:46.679 [11859] iproto V> 00000000: A3 02 D6 5A E4 D9 E7 68 A1 53 8D 53 60 5F 20 3F
[001] 2019-04-05 18:22:46.679 [11859] iproto V> 00000010: D8 E2 D6 E2 A3 02 D6 5A E4 D9 E7 68 A1 53 8D 53
```
Now we can get rid of malloc, and use a preallocated tt_static_buf
instead.
Also, replace a big macro with a small macro and a helper function.

Followup to f645119f

This reverts commit 8be593ce.

Now, as the use-after-free bug in space_truncate() implementation has
been fixed, we can enable this test again.

Follow-up #4093

space_truncate allocates a statement on the stack which is grossly
incorrect as the stack may be purged once the function returns while
box_process_rw expects the statement to be valid until the end of
the transaction. By happy accident, it worked fine until commit
1f7b0d65 ("Require for single statement not autocommit in case of
ddl"), which made it possible to run this function from a transaction
and hence increased the probability of hitting the use-after-free bug.
The fix is trivial: allocate a truncation statement on the region.

Fixes commit 353bcdc5 ("Rework space truncation").

Closes #4093

This commit enables pretest_clean test-run option on 'core = tarantool'
test suites with Lua tests and 'core = app' test suites. Consider #4094
for an example of a problem that is eliminated by this option.

For 'core = tarantool': this option drops non-system spaces, drops data
in system spaces and global variables to the initial state, unloads
packages except build-in ones.

For 'core = app': this option deletes xlog and snap files before run a
test.

test-run doesn't remove global variables that are listed in the
'protected_globals' global variable. Use it for, say, functions that are
defined in an instance file and called from tests.

Consider test-run/README.md for the information how exactly the option
works.

Removed unused cfg_filter() function from test/engine/box.lua.

Fixes #4094.

This reverts commit 14a87bb7.

The test cases generate corrupted xlog files (see #4093) and don't allow
other tests to proceed successfully, so we need to temporary disable
these cases. They should be enabled back in the scope of #4093.

* Added default timeout for wait_cond() (60 sec).
* Updated pyyaml version in requirements.txt.
* Fixed reporting of non-default server fail at start.
* Stop 'proxy' when a new non-default instance fails.
* Added user-defined protected globals for pretest_clean.

In SQL type of constant literal (e.g. 1, 2.5, 'abc') is assigned right
after parsing and saving into struct Expr. Occasionally, type is
re-assigned before emitting opcodes to store literal into VDBE memory.
What is more, for floating point number type is changed to "integer".
This patch fixes this obvious misbehaviour.

Using the const qualifier for complex structures like tuple is bad.
We already have to cast it to drop the const qualifier now and then,
e.g. to increment/decrement the reference counter.

We are planning to wrap struct tuple in a helper struct (aka entry) to
store it in vinyl containers along with a comparison hint (cache, memory
tree, etc). We will be passing this struct by value so we won't be able
to retain const qualifier, because in contrast to a const pointer, one
must initialize a const struct upon definition.

That said, it's time to drop const qualifier of struct tuple everywhere,
like we have already done in case of struct key_def and tuple_format.

These tables won't be used anymore and should be deleted.

Note, this patch breaks backward compatibility between 2.1.1 and
2.1.2, but that's okay as 2.1.1 was beta and we didn't recommend
anyone to use it.

Part of #2843
Follow up #4069

Currently, the memory for index_id is not allocated in VDBE code
in the sql_code_drop_table() and sql_drop_index() functions. This
may lead to SEGMENTATION FAULT.

Needed for #2843

Because sql_normalize_name used to be called twice - to estimate
the size of the name buffer and to process data querying the
UCaseMap object each time performance in SQL felt by 15%.

This patch should eliminate some of the negative effects of using
ICU for name normalization.

Thanks @avtikhon for a bechmark

Follow up e7558062

This patch changes the name of the function used in the port_sql
methods and the name of the member of the result of the execution.

Follow up #3505

It takes random time since SWIM uses random members selection
for each round step. Appeared, that in one of tests choosen time
was too small sometimes. Now it is fixed by just increasing
timeout, but one of forthcoming patches reworks that test in
order to make it faster.

Follow up for f510dc6f

Add row hex printing to log on verbose level. This would be useful
during investigation of errors related to invalid msgpack packet
arrival.

Here's some example output:
```
2019-04-01 16:04:51.629 [31304] iproto V> Corrupted row is: 3D A5 41 55 99 18 A8 08 C2 40 2B BA 50 12 F6 C6 0B 27 66 1C
2019-04-01 16:04:51.629 [31304] iproto xrow.c:133 E> ER_INVALID_MSGPACK: Invalid MsgPack - packet header
```

Related to #4040

Failure detection components allows to find which members are
already dead. It works via pings attached to each round message.
A member, received ping, should respond with an ack. If it is not
done within a timeout, then the ping is considered unacknowledged.
When a number of pings grows to a threshold, the member is
declared DEAD. After more unacked pings it is dropped from the
member table. Unless the GC was turned off.

Part of #3234

The function allows to create a tuple with specific tuple format in C
code using a Lua table, another tuple, or objects on a Lua stack.

Needed for #3276, #3398, #4025

Due to the fact that the allocation of offset_slot in the case of
multikey indexes will become more complicated and will be
necessary for intermediate nodes of the tuple_field tree, we must
move this logic to the tuple_format_add_field that performs
an intermediate nodes allocation for a JSON path.

Needed for #1257

Introduced a new procedure json_path_multikey_offset. This helper
scans the JSON path string and returns the offset of the first character
[*] (the array index placeholder).

We need this function in the scope of the multikey index patchset to
extract the number of keys to be inserted into the index
using JSON subpath that has json_path_multikey_offset() length.

Needed for #1257

This patch is inspired by commit 829c811c ("tuple_compare: cleanup
key_def virtual func setter") and attempts to simplify setting
appropriate tuple_extract_key pointer for plain and json indexes in
key_def_set_extract_func routine. Being split to plain and json blocks
this code becomes easier to understand and extend.

In further patches we need to introduce is_multikey branch and without
this refactoring required amendments turn the key_def_set_extract_func
code into a mess.

Needed for #1257

A problem appears when tests are run in the following order on one
test-run worker:

- sql-tap/select6.test.lua
- sql-tap/gh-4077-iproto-execute-no-bind.test.lua

The latter one fails with the following error:

> Space 'T' already exists

This test does not perform require('sqltester'), where *.{xlog,snap}
files from a previous test are removed, and so the test can observe a
non-clean state of a database.

Now test-run has pretest_clean option that do exactly what sqltester had
been doing: when the option enabled test-run removes *.{xlog,snap} files
before run a 'core = app' test. The only difference that now these files
will be removed for every test in sql-tap test suite, not only for ones
that use sqltester.

Follows up #4077.

The test was introduced in a99d7a0c
('Feature request for a new collation'). It succeeds when tarantool is
linked with a fresh libicu version, but fails with older ones. At least:

* dev-libs/icu-63.1-r1 (Gentoo) -- passes;
* libicu.x86_64 50.1.2-15.el7 (CentOS 7.4) -- fails.

We need to handle different behaviours of libicu versions somehow, maybe
add only stable subset of collations. This will also fix the test and
then it will be enabled back.

Related to #4007.

SWIM's fake file descriptors were implemented to test SWIM with
virtual time and fully controlled network with immediate packet
delivery. One of their features - API to block a file descriptor
and test various failures about it.

But blocked fake fd looks the same as closed fd, and it can
confuse new test's author. Now if an fd is not unblocked at the
end of a test, it leads to a crash. This commit fixes that via
adding explicit difference between blocked and closed fd.

Part of #3234

At least for testing it is necessary to be able to get status of
a member. Now it is always 'alive', but forthcoming
failure-detection component would change it.

Part of #3234