Bug#38934 slave slave until does not work with --replicate-same-server-id

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.

mysql-test/suite/rpl/t/disabled.def

@@ -13,4 +13,3 @@
 rpl_redirect               : Failure is sporadic and and the test is superfluous (mats)
 rpl_innodb_bug28430        : Failure on Solaris Bug #36793
 rpl_flushlog_loop          : BUG#37733 2008-07-23 Sven disabled in 5.1-bugteam. the bug has been fixed in 5.1-rpl: please re-enable when that gets pushed to main
-rpl_server_id2             : Bug#38540 rpl_server_id2 uses show slave status unnecessarily