aftermerge fix

mysql-test/t/subselect.test

@@ -693,7 +693,7 @@ INSERT INTO t1 VALUES (1);
 UPDATE t1 SET i=i+(SELECT MAX(i) FROM (SELECT 1) t) WHERE i=(SELECT MAX(i));
 -- error 1111
 UPDATE t1 SET i=i+1 WHERE i=(SELECT MAX(i));
--- error 1054
+-- error 1109
 UPDATE t1 SET t.i=i+(SELECT MAX(i) FROM (SELECT 1) t);
 drop table t1;