test: flaky hangs replication/election_basic.test.lua test on cluster_create() on OSX

[avtikhon]

| Tarantool 2.7.2-73-gb2fd8f49f
| Target: Darwin-x86_64-RelWithDebInfo
| Build options: cmake . -DCMAKE_INSTALL_PREFIX=/usr/local -DENABLE_BACKTRACE=ON
| Compiler: /Applications/Xcode_12.5.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/cc /Applications/Xcode_12.5.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/2908428769

results file checksum: bd79c8e45a7b307b815c54f8390b074f

osx_11_0.zip

Issue happened on hanged create_cluster() routine:

assert(box.info.election.leader == box.info.id)
 | ---
 | - true
 | ...

box.cfg{                                                                        \
    election_mode = 'off',                                                      \
    election_timeout = old_election_timeout                                     \
}
 | ---
 | ...

--
-- See if bootstrap with election enabled works.
--
SERVERS = {'election_replica1', 'election_replica2', 'election_replica3'}
 | ---
 | ...
test_run:create_cluster(SERVERS, "replication")
 | ---