test: vinyl/errinj test fails under highload

Test "check that all dump/compaction tasks that are in progress at
the time when the server stops are aborted immediately.", but in
real the awaiting time of 1 second is not enough due to runs in
parallel and it fails, like:

[009] --- vinyl/errinj.result Tue Apr 16 16:43:36 2019
[009] +++ vinyl/errinj.reject Wed Apr 17 09:42:36 2019
[009] @@ -530,7 +530,7 @@
[009] ...
[009] t2 - t1 < 1
[009] ---
[009] -- true
[009] +- false
[009] ...
[009] test_run:cmd("cleanup server test")
[009] ---
[009]

in 100 parallel runs the failed delays were found:

[002] +- 1.4104716777802
[022] +- 1.3933029174805
[044] +- 1.4296517372131
[033] +- 1.6380662918091
[001] +- 1.9799520969391
[027] +- 1.7067711353302
[043] +- 1.3778221607208
[034] +- 1.3820221424103
[032] +- 1.3820221424103
[020] +- 1.6275615692139
[050] +- 1.6275615692139
[048] +- 1.1880359649658

Decided to avoid of use the time check at all and change the
ERRINJ_VY_RUN_WRITE_STMT_TIMEOUT to ERRINJ_VY_DUMP_DELAY injection.
In this way the time checks were completely removed.

Next issue met was the error:

vy_quota.c:298 !> SystemError Failed to allocate 2097240 bytes
    in lsregion for vinyl transaction: Cannot allocate memory

That is why the merged 2 subtests were divided into 2 standalone
subtests to be able to set the memory limit of the 2nd subtest to
2097240 value.

Close #4169