fix intermittent failure when sync close beats async ack

git-svn-id: https://svn.apache.org/repos/asf/activemq/trunk@744972 13f79535-47bb-0310-9956-ffa450edef68

activemq-core/src/test/java/org/apache/activemq/broker/BrokerTest.java

@@ -1114,6 +1114,9 @@ public class BrokerTest extends BrokerTestSupport {
             connection1.send(createAck(consumerInfo1, m1, 1, MessageAck.STANDARD_ACK_TYPE));
         }
 
+        // give the async ack a chance to perculate and validate all are currently consumed
+        assertNull(connection1.getDispatchQueue().poll(MAX_NULL_WAIT, TimeUnit.MILLISECONDS));
+ 
         // Close the consumer.
         connection1.request(closeConsumerInfo(consumerInfo1));