test: flaky box/net.box_reload_schema_gh-636.test.lua test

[avtikhon]

Tarantool version:
Tarantool 2.7.0-53-g908d1edd8
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 15

Bug description:

1. https://gitlab.com/tarantool/tarantool/-/jobs/860019787#L4979

artifacts.zip

results file checksum: 42720b688500eb4dc77f2d4b4eda305d

[063] --- box/net.box_reload_schema_gh-636.result	Thu Oct 15 19:08:51 2020
[063] +++ /tmp/tnt/rejects/box/net.box_reload_schema_gh-636.reject	Thu Nov 19 14:24:10 2020
[063] @@ -62,6 +62,7 @@
[063]  ...
[063]  box.space.test:drop()
[063]  ---
[063] +- error: 'Can''t drop space ''test'': the space has grants'
[063]  ...
[063]  box.space.test_old:drop()
[063]  ---
[063] @@ -101,7 +102,6 @@
[063]  ...
[063]  test_run:wait_log('default', 'ER_NO_SUCH_PROC', nil, 10)
[063]  ---
[063] -- ER_NO_SUCH_PROC
[063]  ...
[063]  box.schema.user.revoke('guest', 'execute', 'universe')
[063]  ---
[063] 

2. https://gitlab.com/tarantool/tarantool/-/jobs/852519363#L4969

results file checksum: 263ac84314fd1b2585ad1ee81e8d0dd0

[019] --- box/net.box_reload_schema_gh-636.result	Sat Aug 22 05:06:33 2020
[019] +++ /tmp/tnt/rejects/box/net.box_reload_schema_gh-636.reject	Tue Nov 17 00:10:36 2020
[019] @@ -101,7 +101,6 @@
[019]  ...
[019]  test_run:wait_log('default', 'ER_NO_SUCH_PROC', nil, 10)
[019]  ---
[019] -- ER_NO_SUCH_PROC
[019]  ...
[019]  box.schema.user.revoke('guest', 'execute', 'universe')
[019]  ---
[019] 

Steps to reproduce:

Optional (but very desirable):

• coredump
• backtrace
• netstat