mtr --rr fixes

{10.5} midenok@dull:build$ rr record -h nproc

rr: Saving execution to trace directory `/home/midenok/.local/share/rr/nproc-0'.

8

{10.5} midenok@dull:build$ rr record -h nproc

rr: Saving execution to trace directory `/home/midenok/.local/share/rr/nproc-1'.

6

{10.5} midenok@dull:build$ rr record -h nproc

rr: Saving execution to trace directory `/home/midenok/.local/share/rr/nproc-2'.

3

{10.5} midenok@dull:build$ rr record -h nproc

rr: Saving execution to trace directory `/home/midenok/.local/share/rr/nproc-3'.

5

--- /dev/shm/10.5m/mysql-test/var/2/tmp/check-mysqld_1.result	2020-09-17 12:39:40.051012859 +0300

+++ /dev/shm/10.5m/mysql-test/var/2/tmp/check-mysqld_1.reject	2020-09-17 12:42:01.852733184 +0300

@@ -646,7 +646,7 @@

 THREAD_POOL_OVERSUBSCRIBE	3

 THREAD_POOL_PRIORITY	auto

 THREAD_POOL_PRIO_KICKUP_TIMER	1000

-THREAD_POOL_SIZE	7

+THREAD_POOL_SIZE	2

 THREAD_POOL_STALL_LIMIT	500

 THREAD_STACK	299008

 TIME_FORMAT	%H:%i:%s

  SELECT * FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES

    WHERE variable_name NOT IN ('timestamp')

     AND variable_name not like "Last_IO_Err*"

     AND variable_name != 'INNODB_IBUF_MAX_SIZE'

     AND variable_name != 'INNODB_USE_NATIVE_AIO'

     AND variable_name != 'INNODB_BUFFER_POOL_LOAD_AT_STARTUP'

     AND variable_name not like 'GTID%POS'

     AND variable_name != 'GTID_BINLOG_STATE'

   ORDER BY variable_name;