Replication tests cleanup and consolidation.


ReplicationTestCase.java
Added remove(ReplicationServer...) and stop(ReplicationBroker...).

*Test.java:
Used the new methods from ReplicationTestCase.
Used Arrays.fill().
Removed various redundant methods that had been extracted in the past:
- GroupIdHandshakeTest.clear()
- ReplicationServerFailoverTest.clear()
- ExternalChangeLogTest.stop()
- ReplicationServerTest.stop()
- ReplicationServerTest.removeRsAndChangeLog()
- ReplicationDomainTest.remove())

AssuredReplicationServerTest.java:
Removed all the rs*Port fields, replaced by rsPorts.
Removed all the fakeRd* fields, replaced by fakeRDs.
Extracted methods disableService(), shutdown(), assertFakeDSReceivedAndAcked(), assertFakeRDNbReceivedUpdates(), assertFakeRSNbReceivedUpdates(), checkDSNothingReceivedOrSent(), assertContainsOnly().
Used more the checkDSSentAndAcked(), checkDSReceivedAndAcked().
Inlined on createFakeReplicationDomain().
Removed all sorts of assertNotNull() where the code could never be null.