Use include/sync_with_master_gtid.inc instead of --sync_with_master to avoid a
race in the test case.
In parallel replication, the old-style slave position (which is used by
--sync_with_master) is updated out-of-order between parallel threads. This
makes it possible for the position to be updated past DROP TEMPORARY TABLE t2
just before the commit of INSERT INTO t1 SELECT * FROM t2 becomes visible.
In this case, there is a small window where a SELECT just after
--sync_with_master may not see the changes from the INSERT.