Fix intermittent failure in testWriteTransactionWithSingleShard

Fix intermittent failure in testWriteTransactionWithSingleShard

DistributedDataStoreRemotingIntegrationTest.testWriteTransactionWithSingleShard
fails intermittently with tell-based protocol in verifyCars after it has
reinstated the follower where it's expecting just car1 but the
data tree contains car 1 and car2. This is b/c the delete transaction for car2
prior to reinstatement wasn't applied on recovery due to the corresponding
ApplyJournalEntries message missing from the persisted journal. The test
expects 2 ApplyJournalEntries messages to be persisted corresponding to the
2 transactions but tell-based persists other payloads as well so there may
be 3 ApplyJournalEntries messages. I changed the code to handle this case.

Also the assertion failure in verifyCars caused it to bypass shutting down
the ActorSystem which resulted in several other failures in tests that try to
use the same port configuration due to the port already in use. So I made
changes to ensure ActorSystems are shutdown properly.

Change-Id: Id6316d71fcd9eb3e768c6b1f676fa0e9be1287a2
Signed-off-by: Tom Pantelis <tompantelis@gmail.com>