Fix test failure seen in buildbot on power8.

GTID order in @@gtid_binlog_pos depends on internal hash order,
so requires --replace_result for stable test output.

mysql-test/suite/rpl/r/rpl_gtid_until.result

@@ -168,7 +168,7 @@ a
 include/stop_slave.inc
 CREATE TABLE t3 (a INT);
 DROP TABLE t3;
-START SLAVE UNTIL master_gtid_pos='1-1-5,2-1-5,0-1-6';
+START SLAVE UNTIL master_gtid_pos='UNTIL_CONDITION';
 include/wait_for_slave_to_stop.inc
 SHOW CREATE TABLE t3;
 Table	Create Table

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

@@ -175,6 +175,7 @@ DROP TABLE t3;
 --save_master_pos
 
 --connection server_2
+--replace_result $until_condition UNTIL_CONDITION
 eval START SLAVE UNTIL master_gtid_pos='$until_condition';
 --source include/wait_for_slave_to_stop.inc
 SHOW CREATE TABLE t3;