Bug#38540 rpl_server_id2 uses show slave status unnecessarily
            
Slave did not perform any event recorded into the relay log from some
different master when it was started with --replicate-same-server-id.
The reason appeared to be a consequence of BUG#38734 which stopped the
sql thread at its startup time.
      
The real fixes for the current bug are in the patch for BUG#38734.
This changeset carries only a regression test for the bugs.  Bug#38540
gets fixed too by means of eliminating an extra show slave status.