Fix ENG-5310 and add tests.
remove unnecessary assert.
count batches submitted and wait for batch ack before putting end on failureQueue.
ENG-5310 - changes per review.
Merge branch 'ENG-5310-last-batch-drain' of https://github.com/VoltDB/voltdb into ENG-5310-last-batch-drain

Conflicts:
	src/frontend/org/voltdb/utils/CSVPartitionProcessor.java