MDEV-11201: gtid_ignore_duplicates incorrectly ignores statements when GTID replication is not enabled

When master_use_gtid=no, the IO thread loads the slave GTID state from
the master during connect. This races with the SQL thread when
gtid_ignore_duplicates=1. If an event is in the relay log from before
the new connect and has not been applied yet, moving the slave
position causes the SQL thread to think that event should be skipped
due to gtid_ignore_duplicates=1.

This patch simply disables gtid_ignore_duplicates when not using GTID,
which seems to be what one would expect.