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

[avtikhon]

Tarantool version:
Tarantool 2.6.0-93-gc412e65bf
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

Bug description:
https://gitlab.com/tarantool/tarantool/-/jobs/746962633#L3974
results file checksum: cca5df51000ec0076450a6b1a8b21053

[012] --- box/net.box_reconnect_after.result	Sat Sep 12 18:54:38 2020
[012] +++ box/net.box_reconnect_after.reject	Sun Sep 20 01:16:52 2020
[012] @@ -25,7 +25,7 @@
[012]  ...
[012]  c.state
[012]  ---
[012] -- closed
[012] +- error_reconnect
[012]  ...
[012]  c = nil
[012]  ---
[012] 

Steps to reproduce:

1. enable parallel testing in test-run:

commit 5f55b46dc56f95ca98e0277ee8cfb75210a8bbfd (HEAD, origin/avtikhon/tmp_all_flaky_fixes_min_prs)
Author: Alexander V. Tikhonov <avtikhon@tarantool.org>
Date:   Thu Dec 3 09:53:02 2020 +0000

    Enable fragile list tests run in parallel

diff --git a/lib/worker.py b/lib/worker.py
index a8643fe..698e9d2 100644
--- a/lib/worker.py
+++ b/lib/worker.py
@@ -89,7 +89,7 @@ def get_task_groups():
             res[key + '_fragile'] = {
                 'gen_worker': gen_worker,
                 'task_ids': fragile_task_ids,
-                'is_parallel': False,
+                'is_parallel': suite.is_parallel(),
                 'show_reproduce_content': suite.show_reproduce_content(),
             }
     return res

2. remove test from fragile list:

diff --git a/test/box/suite.ini b/test/box/suite.ini
index d5f72e559..827ae88f3 100644
--- a/test/box/suite.ini
+++ b/test/box/suite.ini
@@ -68,10 +68,6 @@ fragile = {
             "issues": [ "gh-5327" ],
             "checksums": [ "d6136f214b81556b1858e05970a90963" ]
         },
-        "net.box_reconnect_after.test.lua": {
-            "issues": [ "gh-5333" ],
-            "checksums": [ "cca5df51000ec0076450a6b1a8b21053" ]
-        },
         "lua.test.lua": {
             "issues": [ "gh-5351" ],
             "checksums": [ "6b0a398df80683a968d270fdc0efdf50", "5d6a9c9a1b08cf5cd3f9bbdc2e0dfe3a" ]

3. start testing with high load on OSX host:

l=0 ; while ./test-run.py -j200  box/ `for s in {1..5} ; do echo replication/election_qsync_stress.test.lua ; done`     `for r in {1..2} ; do echo box/ ; done`     2>/dev/null ; do l=$(($l+1)) ; echo ======== $l ============= ; fi ; done

Optional (but very desirable):

• coredump
• backtrace
• netstat