Galera MTR Tests: Attempt to remove rare sporadic failures in...

Galera MTR Tests: Attempt to remove rare sporadic failures in galera_transaction_replay.test by waiting for all transactions to get blocked before proceeding.

mysql-test/suite/galera/t/galera_transaction_replay.test

@@ -38,6 +38,14 @@ SET SESSION wsrep_sync_wait = 0;
 --connection node_2
 UPDATE t1 SET f2 = 'c' WHERE f1 = 2;
 
+# Wait for both transactions to be blocked
+--connection node_1a
+--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE STATE = 'System lock';
+--source include/wait_condition.inc
+
+--let $wait_condition = SELECT COUNT(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE STATE = 'init' AND INFO = 'COMMIT';
+--source include/wait_condition.inc
+
 # Unblock the commit
 --connection node_1a
 SET GLOBAL wsrep_provider_options = 'dbug=';