Merge 10.3 into 10.4

mysql-test/main/table_elim.result

@@ -279,7 +279,7 @@ insert into t2 values
 explain select t1.* from t1 left join t2 on t2.a=t1.a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t1	index	NULL	PRIMARY	10	NULL	2	Using index
-1	SIMPLE	t2	ref	a	a	3	test.t1.a	2	Using where
+1	SIMPLE	t2	ref	a	a	3	test.t1.a	1	Using where
 drop table t1, t2;
 #
 # check UPDATE/DELETE that look like they could be eliminated