The test case creates two temporary tables, then closes the
connection, waits for it to disconnect, then syncs the slave with
the master, checks for remaining opened temporary tables on
slave (which should be 0) and finally drops the used
database (mysqltest).
      
Unfortunately, sometimes, the test fails with one open table on
the slave. This seems to be caused by the fact that waiting for
the connection to be closed is not sufficient. The test needs to
wait for the DROP event to be logged and only then synchronize
the slave with the master and proceed with the check. This is
caused by the asynchronous nature of the disconnect wrt
binlogging of the DROP temporary table statement.
      
We fix this by deploying a call to wait_for_binlog_event.inc
on the test case, which makes execution to wait for the DROP
temp tables event before synchronizing master and slave.