Bug #104377 mysql test main.ssl-big error: too many connections

Description:
when i do the mysql test on case main.ssl-big, it report error: ERROR 1040 (HY000):Too many connections
mysqltest: Query 'connect ssl_con, localhost,root,,,SSL' failed.

How to repeat:
./mtr main.ssl-big

Hello Silong zheng,

Thank you for the report and feedback.
Observed issue in debug builds.

regards,
Umesh

- release build
 ./mtr main.ssl-big
Logging: ./mtr  main.ssl-big
MySQL Version 8.0.26
Checking supported features
Using 'all' suites
Collecting tests
Removing old var directory
Creating var directory '/export/home/tmp/ushastry/mysql-8.0.26/mysql-test/var'
Installing system database
Using parallel: 1

==============================================================================
                  TEST NAME                       RESULT  TIME (ms) COMMENT
------------------------------------------------------------------------------
[ 50%] main.ssl-big                              [ pass ]  21923
[100%] shutdown_report                           [ pass ]
------------------------------------------------------------------------------
The servers were restarted 0 times
The servers were reinitialized 0 times
Spent 21.923 of 31 seconds executing testcases

Completed: All 2 tests were successful.

-- debug build

./mtr --debug-server main.ssl-big
Logging: ./mtr  --debug-server main.ssl-big
MySQL Version 8.0.26
Checking supported features
 - Binaries are debug compiled
Using 'all' suites
Collecting tests
Checking leftover processes
Removing old var directory
Creating var directory '/export/home/tmp/ushastry/mysql-8.0.26/mysql-test/var'
Installing system database
Using parallel: 1

==============================================================================
                  TEST NAME                       RESULT  TIME (ms) COMMENT
------------------------------------------------------------------------------
[ 50%] main.ssl-big                              [ fail ]
        Test ended at 2021-07-21 11:15:46

CURRENT_TEST: main.ssl-big
mysqltest: At line 35: Query 'connect  ssl_con,localhost,root,,,,,SSL' failed.
ERROR 1040 (HY000): Too many connections

The result from queries just before the failure was:
DROP TABLE IF EXISTS t1, t2;
create table t1 (a int);
safe_process[20186]: Child process: 20187, exit: 1

 - the logfile can be found in '/export/home/tmp/ushastry/mysql-8.0.26/mysql-test/var/log/main.ssl-big/ssl-big.log'

[100%] shutdown_report                           [ pass ]
------------------------------------------------------------------------------
The servers were restarted 0 times
The servers were reinitialized 0 times
Spent 0.000 of 39 seconds executing testcases

Completed: Failed 1/2 tests, 50.00% were successful.

Failing test(s): main.ssl-big

The log files in var/log may give you some hint of what went wrong.

If you want to report this error, please read first the documentation
at http://dev.mysql.com/doc/mysql/en/mysql-test-suite.html

mysql-test-run: *** ERROR: there were failing test cases

Documented fix as follows in the MySQL 8.0.29 changelog:

    The test program main.ssl-big error failed with -Too many
    connections-.

    Our thanks to Facebook for the contribution.

Closed.

Also fixes BUG#104446.