Bug #27531: 5.1 part of the fix

- Renamed "Using join cache" to "Using join buffer".
- "Using join buffer" is now printed on the last
  table that "reads" from the join buffer cache.


mysql-test/r/archive_gis.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/compress.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/ctype_utf8.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/derived.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/distinct.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/func_group.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/func_group_innodb.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/gis.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/greedy_optimizer.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/group_by.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/group_min_max.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/index_merge_myisam.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/information_schema.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/innodb_gis.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/innodb_mysql.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/join.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/join_nested.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/key_diff.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/myisam.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/ndb_condition_pushdown.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/ndb_gis.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/range.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/row.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/select.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/ssl.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/ssl_compress.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/subselect.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/subselect3.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/union.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
mysql-test/r/view.result:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.
sql/sql_select.cc:
  Bug #27531: renamed "Using join cache" to "Using join buffer"
  and moved to the last table in the batch.

mysql-test/r/func_group.result

@@ -613,8 +613,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain
 select max(t1.a3), min(t2.a2) from t1, t2 where t1.a2 = 2 and t1.a3 < 'MIN' and t2.a3 > 'CA';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	range	k1	k1	7	NULL	1	Using where; Using index; Using join cache
-1	SIMPLE	t2	range	k1	k1	3	NULL	4	Using where; Using index
+1	SIMPLE	t1	range	k1	k1	7	NULL	1	Using where; Using index
+1	SIMPLE	t2	range	k1	k1	3	NULL	4	Using where; Using index; Using join buffer
 explain
 select min(a4 - 0.01) from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -650,8 +650,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain
 select concat(min(t1.a1),min(t2.a4)) from t1, t2 where t2.a4 <> 'AME';
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	range	k2	k2	4	NULL	6	Using where; Using index; Using join cache
-1	SIMPLE	t1	index	NULL	PRIMARY	3	NULL	15	Using index
+1	SIMPLE	t2	range	k2	k2	4	NULL	6	Using where; Using index
+1	SIMPLE	t1	index	NULL	PRIMARY	3	NULL	15	Using index; Using join buffer
 drop table t1, t2;
 create table t1 (a char(10));
 insert into t1 values ('a'),('b'),('c');