Update matching_candidates_in_table() to treat all conditions similar

Fixed also that the 'with_found_constraint parameter' to
matching_candidates_in_table() is as documented: It is now true only
if there is a reference to a previous table in the WHERE condition for
the current examined table (as it was originally documented)

Changes in test results:
- Filtered was 25% smaller for some queries (expected).
- Some join order changed (probably because the tables had very few rows).
- Some more table scans, probably because there would be fewer returned
  rows.
- Some tests exposes a bug that if there is more filtered rows, then the
  cost for table scan will be higher. This will be fixed in a later commit.

1 files changed, 3 insertions, 3 deletions

diff --git a/mysql-test/main/subselect_no_opts.result b/mysql-test/main/subselect_no_opts.result
index 15688fc1717..51386376d80 100644
--- a/mysql-test/main/subselect_no_opts.result
+++ b/mysql-test/main/subselect_no_opts.result
@@ -1506,10 +1506,10 @@ a
 explain extended select * from t2 where t2.a in (select t1.a from t1,t3 where t1.b=t3.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	index	NULL	a	5	NULL	4	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t3	index	a	a	5	NULL	3	100.00	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	ref	a	a	10	func,test.t3.a	1167	100.00	Using index
+2	DEPENDENT SUBQUERY	t1	ref	a	a	5	func	1001	100.00	Using index
+2	DEPENDENT SUBQUERY	t3	index	a	a	5	NULL	3	75.00	Using where; Using index; Using join buffer (flat, BNL join)
 Warnings:
-Note	1003	/* select#1 */ select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(/* select#2 */ select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where `test`.`t1`.`b` = `test`.`t3`.`a` and <cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))
+Note	1003	/* select#1 */ select `test`.`t2`.`a` AS `a` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`a`,<exists>(/* select#2 */ select `test`.`t1`.`a` from `test`.`t1` join `test`.`t3` where `test`.`t3`.`a` = `test`.`t1`.`b` and <cache>(`test`.`t2`.`a`) = `test`.`t1`.`a`))
 insert into t1 values (3,31);
 select * from t2 where t2.a in (select a from t1 where t1.b <> 30);
 a