ISPN-3530 ISPN-1855 Keep per-cache CH to route requests correctly

* fixed HotRodManagerIT tests: cannot pass null as cache name
ISPN-4472 Upgrade TestNG from 6.8 to 6.8.8
Change ReplicatedCHFactory to only replace leavers in updateMembers()

Uneven primary ownership should be dealt with in rebalance() only.
Delegate the isBalanced() check in DefaultRebalancePolicy to the CH factory

Allows waitForRehashToComplete() to work even if the CH factory allocated
less than numOwners owners to each segment.