test: flaky box/net.box_get_connection_object.test.lua

[avtikhon]

Tarantool version:
Tarantool 2.7.0-71-gbf74a97fe
Target: Darwin-x86_64-RelWithDebInfo
Build options: cmake . -DCMAKE_INSTALL_PREFIX=/usr/local -DENABLE_BACKTRACE=ON
Compiler: /Library/Developer/CommandLineTools/usr/bin/cc /Library/Developer/CommandLineTools/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

OS version:
OSX 13

Bug description:
https://gitlab.com/tarantool/tarantool/-/jobs/865068930#L4721

artifacts.zip

results file checksum: 80f104406a762aed2119108aa33be73d

[009] --- box/net.box_get_connection_object.result	Wed Sep 30 17:19:31 2020
[009] +++ /tmp/tnt/rejects/box/net.box_get_connection_object.reject	Sun Nov 22 04:18:01 2020
[009] @@ -22,7 +22,7 @@
[009]  ...
[009]  c:ping()
[009]  ---
[009] -- true
[009] +- false
[009]  ...
[009]  c.space.test ~= nil
[009]  ---
[009] 

Steps to reproduce:

Optional (but very desirable):

• coredump
• backtrace
• netstat