MDEV-8294: Inconsistent behavior of slave parallel threads at runtime

Follow-up patch to temporarily avoid a sporadic failure in the test
rpl.rpl_000011 due to MDEV-8301.

There is a window during thread exit where the global status is
counted incorrectly - the contribution for the exiting thread is
counted twice. The patch for MDEV-8294 made this window visible to the
test case rpl.rpl_000011, causing it to sporadically fail. Temporarily
silence this with a wait for the expected value; can be removed once
MDEV-8294 is fixed.

mysql-test/suite/rpl/t/rpl_000011.test

@@ -11,6 +11,12 @@ insert into t1 values(1);
 sync_slave_with_master; 
 show global status like 'com_insert';
 stop slave;
+# Temporary work-around for bug MDEV-8301. There is a small window during
+# thread exit where the local status values of a thread are counted twice
+# in the global status. Remove this wait_condition.inc once MDEV-8301 is
+# fixed.
+--let $wait_condition= SELECT variable_value=1 FROM information_schema.global_status WHERE variable_name="Com_insert";
+--source include/wait_condition.inc
 show global status like 'com_insert';
 --source include/wait_for_slave_to_stop.inc
 start slave;