KAFKA-19685: Add possibility of passing in revoked partitions in task precommit

[zheguang]

This patch clarifies SinkTask.precommit, which may see revoked partitions during rebalancing and stopping.

As pointed out in KAFKA-19685, there is a difference in whether SinkTask.precommit sees revoked partitions during iteration or stopping.

This difference appears to be intentional for correctness w.r.t. rebalance

• During iteration, partition ownership may change due to rebalanced, so revoked partitions should be cleaned up at each poll, to avoid committing offsets for partitions no longer owned
• During stopping, all current offsets are committed regardless of partition ownership to record the final state. The task is ending its lifecycle and no new records will be processed.