REPLICATION HANG

Problem:
=======

With MTS, GTIDs and auto positioning enabled, when a worker applies a
partial transaction left on relaylog by an IO thread reconnection, it
will wait for the XID log event to commit the transaction.

Unfortunately, the SQL thread coordinator will reach the master's
ROTATE event on the next relaylog file and will wait for all workers
to finish their tasks before applying the ROTATE.

Analysis:
========

As the whole transaction is retrieved again by the IO thread after the
reconnection, the slave must rollback the partial transaction once
noticing this ROTATE from the master.

This bug reports the same issue already fixed by BUG#17326020, and the
reported issue is not reproducible anymore. So, this patch is just
adding a new test case.