remove non-working debug assert

and restore the test modified in the same commit
(the non-replication related deadlock will be reported separately)

mysql-test/suite/rpl/t/rpl_slave_grp_exec.test

@@ -101,8 +101,7 @@ ALTER TABLE t1 ADD PRIMARY KEY (a);
 ALTER TABLE t2 ADD PRIMARY KEY (a);
 ALTER TABLE t3 ADD PRIMARY KEY (a);
 
-#--sync_slave_with_master 
---connection slave
+--sync_slave_with_master
 RENAME TABLE t3 TO t3_bak;
 
 --connection master

mysys/my_error.c

@@ -112,9 +112,6 @@ void my_error(uint nr, myf MyFlags, ...)
   char ebuff[ERRMSGSIZE];
   DBUG_ENTER("my_error");
   DBUG_PRINT("my", ("nr: %d  MyFlags: %lu  errno: %d", nr, MyFlags, errno));
-
-  if (errno == 1213)
-    DBUG_ASSERT(0);
 
   if (!(format = my_get_err_msg(nr)))
     (void) my_snprintf(ebuff, sizeof(ebuff), "Unknown error %d", nr);