main.start_slave_until fails sporadically

CURRENT_TEST: main.start_slave_until

mysqltest: At line 64: query 'START slave until MASTER_LOG_FILE='master-bin.000001', MASTER_LOG_POS=4' succeeded - should have failed with error ER_BAD_SLAVE (1200)...

The result from queries just before the failure was:

START slave until MASTER_LOG_FILE='master-bin.000001', MASTER_LOG_POS=4, MASTER_USE_GTID=NO, MASTER_DEMOTE_TO_SLAVE=1;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'MASTER_USE_GTID=NO, MASTER_DEMOTE_TO_SLAVE=1' at line 1

START slave until RELAY_LOG_FILE='master-bin.000001', RELAY_LOG_POS=4, MASTER_USE_GTID=NO, MASTER_DEMOTE_TO_SLAVE=1;

ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'MASTER_USE_GTID=NO, MASTER_DEMOTE_TO_SLAVE=1' at line 1

ER_BAD_SLAVE: Dummy error which should be treated as a passing test as this is a parser test not a logical one

START slave until MASTER_LOG_FILE='master-bin.000001', RELAY_LOG_POS=4;

ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL

START slave until RELAY_LOG_FILE='master-bin.000001', MASTER_LOG_POS=4;

ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL

START slave until MASTER_LOG_FILE='master-bin.000001';

ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL

START slave until RELAY_LOG_FILE='master-bin.000001';

ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL

START slave until RELAY_LOG_POS=4;

ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL

START slave until MASTER_LOG_POS=4;

ERROR HY000: Incorrect parameter or combination of parameters for START SLAVE UNTIL

START slave until MASTER_LOG_FILE='master-bin.000001', MASTER_LOG_POS=4;