test: flaky hangs replication/gh-5435-qsync-clear-synchro-queue-commit-all.test.lua on wait_fullmesh() on OSX

[avtikhon]

Tarantool 2.9.0-113-g29025bce7
| Target: Darwin-x86_64-RelWithDebInfo
| Build options: cmake . -DCMAKE_INSTALL_PREFIX=/Users/runner/work/tarantool/tarantool/static-build/tarantool-prefix -DENABLE_BACKTRACE=TRUE
| Compiler: /Applications/Xcode_12.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc /Applications/Xcode_12.4.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/c++
| C_FLAGS: -Wno-unknown-pragmas -fexceptions -funwind-tables -fno-omit-frame-pointer -fno-stack-protector -fno-common -msse2 -std=c11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts -Wno-gnu-alignof-expression -Werror
| CXX_FLAGS: -Wno-unknown-pragmas -fexceptions -funwind-tables -fno-omit-frame-pointer -fno-stack-protector -fno-common -msse2 -std=c++11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts -Wno-invalid-offsetof -Wno-gnu-alignof-expression -Werror

Issue:
https://github.com/tarantool/tarantool/runs/2899700903#step:4:9536

replication/gh-5435-qsync-clear-synchro-queue-commit-all.test.lua

results file checksum: d1c9565e92bca6bce6f5e0f23ad26dbe

static_build_cmake_osx_15.zip

Test result file showing that test hanged on test_run:wait_fullmesh():

-- test-run result file version 2
test_run = require('test_run').new()
 | ---
 | ...

--
-- gh-5435: make sure the new limbo owner commits everything there is left in
-- the limbo from an old owner.
--

SERVERS = {'election_replica1', 'election_replica2', 'election_replica3'}
 | ---
 | ...

test_run:create_cluster(SERVERS, "replication", {args='2 0.4'})
 | ---
 | ...
test_run:wait_fullmesh(SERVERS)