ContinuousQueryObjectStorageTest takes too long

ContinuousQueryObjectStorageTest needs to check that the client receives the events that match the query and only those events, so it waits for a while to confirm that the server isn't sending any delayed events.

However, the wait duration is too long: 5 seconds for the joined queue, and 5 more seconds for the left queue. Since test methods repeat the check after each cache modification, the test ends up taking over 2 minutes (with 1 minute in testContinuousQuery alone).