Problem: master binlog has 'create table t1'. Master binlog
was removed before slave could replicate it. In test's cleanup
code, master did 'drop table t1', which caused slave sql
thread to stop with an error since slave sql thread did not
know about t1.
Fix: t1 is just an auxiliary construction, only needed on
master. Hence, we turn off binlogging before t1 is created,
drop t1 as soon as we don't need it anymore, and then turn
on binlogging again.