ISPN-4499 Prevent shadowing user-defined jgroups configuration file
ISPN-4521 ReplicationQueueTest.testReplicationQueueMultipleThreads
random failures

* Updated test to use proper assertions
* Changed test to use eventually
* Changed test threading to use thread pool
Revamped AbstractIninfispanTest threading handling.  Also fixed up
erroneous use of CountDownLatch to try to have threads run at the
same time.