fix flaky AMQ6366Test (#1895)

Author: gurpartap3697

activemq-unit-tests/src/test/java/org/apache/activemq/usecases/AMQ6366Test.java

@@ -69,6 +69,7 @@ protected void testNonDurableReceiveThrougRestart(final String pubBroker, final
 
         startAllBrokers();
         waitForBridgeFormation();
+        waitForMinTopicRegionConsumerCount(conBroker, 1);
 
         final MessageConsumer client = createDurableSubscriber(conBroker, dest, "sub1");
         client.close();