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
ISPN-4137 Transaction executed multiple times due to forwarded CommitCommand

Make rollback commands synchronous
Move stuff from AbstraceEnlistmentAdapter to TransactionCoordinator.