ClusterQueue and QueueClientRequest unit tests

I would use a 

```
assertEventually(new AssertTask(){
  void run(){
       assertEquals(queue1, asList("item1","item2",... 
  }
}
```
Perhaps even pull this out into a assertEqualsEventually(...) since you also need it for other method in this class. This is a lot cleaner than this approach with contains.. 

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