Fixed the innodb_ext_key test by adding replace_column

mysql-test/r/innodb_ext_key.result

@@ -804,5 +804,5 @@ PRIMARY KEY(pk)
 INSERT INTO t2 SELECT a,a FROM t1;
 EXPLAIN SELECT pk FROM t2 FORCE INDEX(k1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	index	NULL	k1	23	NULL	10	Using index
+1	SIMPLE	t2	index	NULL	k1	23	NULL	#	Using index
 DROP TABLE t1,t2;

mysql-test/t/innodb_ext_key.test

@@ -622,6 +622,7 @@ CREATE TABLE t2 (
 )ENGINE=INNODB;
 
 INSERT INTO t2 SELECT a,a FROM t1;
+--replace_column 9 #
 EXPLAIN SELECT pk FROM t2 FORCE INDEX(k1);
 
 DROP TABLE t1,t2;