MDEV-20372 - fix thread_pool_info

In rare cases, both listener and worker can do poll at the same time
(one of them will return events, another one no events)

Fix test query to account for it.

mysql-test/main/thread_pool_info.result

@@ -56,9 +56,9 @@ FLUSH THREAD_POOL_STATS;
 SELECT SUM(DEQUEUES_BY_LISTENER+DEQUEUES_BY_WORKER)  FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
 SUM(DEQUEUES_BY_LISTENER+DEQUEUES_BY_WORKER)
 1
-SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER) FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
-SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER)
-2
+SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER)  BETWEEN 2 AND 3 FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
+SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER)  BETWEEN 2 AND 3
+1
 DESC INFORMATION_SCHEMA.THREAD_POOL_WAITS;
 Field	Type	Null	Key	Default	Extra
 REASON	varchar(16)	NO			

mysql-test/main/thread_pool_info.test

@@ -29,7 +29,7 @@ SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER) > 0 FROM INFORMATION_SCHEMA.THREAD
 --disable_ps_protocol
 FLUSH THREAD_POOL_STATS;
 SELECT SUM(DEQUEUES_BY_LISTENER+DEQUEUES_BY_WORKER)  FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
-SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER) FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
+SELECT SUM(POLLS_BY_LISTENER+POLLS_BY_WORKER)  BETWEEN 2 AND 3 FROM INFORMATION_SCHEMA.THREAD_POOL_STATS;
 --enable_ps_protocol
 
 #I_S.THREAD_POOL_WAITS

mysql-test/unstable-tests

@@ -173,7 +173,6 @@ main.status                           : MDEV-13255 - Wrong result
 main.subselect                        : MDEV-20551 - Valgrind failure
 main.subselect_innodb                 : MDEV-10614 - Wrong result
 main.tc_heuristic_recover             : MDEV-14189 - Wrong result
-main.thread_pool_info                 : MDEV-20372 - thread_pool_info fails randomly in 10.5
 main.timezone2                        : Modified in 10.4.12
 main.tls_version                      : MDEV-21965 - old TLS versions don't work on latest Debian and Ubuntu releases
 main.tls_version1                     : MDEV-21965 - old TLS versions don't work on latest Debian and Ubuntu releases