increase timeouts for multiple change streams test case so it passes for H2

Author: jmoghisi

test-common/src/main/java/de/bwaldvogel/mongo/backend/AbstractOplogTest.java

@@ -467,10 +467,10 @@ public void testMultipleChangeStreams() throws InterruptedException {
             Flowable.fromPublisher(asyncCollection.insertOne(json("_id: 2, bu: 'abc'"))),
             Flowable.fromPublisher(asyncCollection.insertOne(json("_id: 3, bu: 'xyz'"))),
             Flowable.fromPublisher(asyncCollection.insertOne(json("_id: 4, bu: 'abc'")))
-        ).test().awaitDone(5, TimeUnit.SECONDS).assertComplete();
+        ).test().awaitDone(15, TimeUnit.SECONDS).assertComplete();
 
         final Map<Integer, List<ChangeStreamDocument<Document>>> results = streamSubscriber
-            .awaitDone(15, TimeUnit.SECONDS)
+            .awaitDone(30, TimeUnit.SECONDS)
             .assertComplete()
             .assertValueCount(1)
             .values().get(0);