failure to cleanup of table

The test case was not dropping a table before exiting (ie, it was
not cleaning itself after execution). In this case, the warning
message stating that the test did not do a proper cleanup was
deterministic (which can be annoying).

I have found other tests cases on which mtr sporadically reports
that they have not cleaned up after execution:

 - rpl_ndb_circular
 - rpl_failed_optimize

In this case, the master was dropping a table but there was no
synchronization between the slave and the master.

This patch addresses the rpl_ndb_circular_simplex case by adding
the missing DROP table. The other cases are fixed by deploying
the missing sync_slave_with_master instruction.