SGF-884 - Adapt to API changes introduced in Pivotal GemFire 9.8.4.

src/test/java/org/springframework/data/gemfire/test/StubAsyncEventQueueFactory.java

@@ -150,6 +150,11 @@ public class StubAsyncEventQueueFactory implements AsyncEventQueueFactory {
 		return this;
 	}
 
+	@Override
+	public AsyncEventQueueFactory pauseEventDispatching() {
+		return this;
+	}
+
 	@Override
 	public AsyncEventQueueFactory removeGatewayEventFilter(final GatewayEventFilter gatewayEventFilter) {
 		gatewayEventFilters.remove(gatewayEventFilter);