test: set unix sockets for iproto at core = app

Set hard-coded unix sockets for iproto connections at core = app.
Added its option in *-tap/suites.ini files and fixed test for it.
Fix helped to handle the problem with 'Address already in use' error.
Check the previous commit that set the use of sockets:

60f84cbf ('test: use unix sockets for iproto connections')

Test sql-tap/gh-4077-iproto-execute-no-bind.test.lua removed from
fragiled list.

Closes #4459

test/app-tap/suite.ini

@@ -4,3 +4,4 @@ description = application server tests (TAP)
 lua_libs = lua/require_mod.lua lua/serializer_test.lua
 is_parallel = True
 pretest_clean = True
+use_unix_sockets_iproto = True

test/app-tap/tarantoolctl.test.lua

@@ -465,12 +465,9 @@ else
     local remote_path = create_script(dir, 'remote.lua', remote_code)
     test_run:cmd(("create server remote with script='%s'"):format(remote_path))
     test_run:cmd("start server remote")
-    local port = tonumber(
-        test_run:eval("remote",
-                      "return require('uri').parse(box.cfg.listen).service")[1]
-    )
+    local listen_uri = test_run:eval("remote", "return box.cfg.listen")[1]
 
-    local command_base = ('tarantoolctl play localhost:%d filler/00000000000000000000.xlog'):format(port)
+    local command_base = ('tarantoolctl play %s filler/00000000000000000000.xlog'):format(listen_uri)
 
     local status, err = pcall(function()
         test:test("fill and test play output", function(test_i)

test/box-tap/suite.ini

@@ -3,5 +3,6 @@ core = app
 description = Database tests with #! using TAP
 is_parallel = True
 pretest_clean = True
+use_unix_sockets_iproto = True
 fragile = cfg.test.lua     ; gh-4344
           key_def.test.lua ; gh-4252

test/sql-tap/suite.ini

@@ -29,5 +29,5 @@ long_run = gh-3332-tuple-format-leak.test.lua, gh-3083-ephemeral-unref-tuples.te
 config = engine.cfg
 show_reproduce_content = False
 pretest_clean = True
-fragile = gh-4077-iproto-execute-no-bind.test.lua ; gh-4459
-          selectG.test.lua                        ; gh-4458
+use_unix_sockets_iproto = True
+fragile = selectG.test.lua                        ; gh-4458