Making group_by test stable

mysql-test/r/group_by.result

@@ -2796,15 +2796,15 @@ drop table t1;
 # MDEV-20922: Adding an order by changes the query results
 #
 CREATE TABLE t1(a int, b int);
-INSERT INTO t1 values (1, 100), (2, 200), (3, 100), (4, 200);
+INSERT INTO t1 values (1, 100), (2, 200), (3, 100), (4, 200), (5, 200);
 create view v1 as select a, b+1 as x from t1;
 SELECT x, COUNT(DISTINCT a) AS y FROM v1 GROUP BY x ORDER BY y;
 x	y
 101	2
-201	2
+201	3
 SELECT b+1 AS x, COUNT(DISTINCT a) AS y FROM t1 GROUP BY x ORDER BY y;
 x	y
 101	2
-201	2
+201	3
 drop view v1;
 drop table t1;

mysql-test/t/group_by.test

@@ -1920,7 +1920,7 @@ drop table t1;
 --echo #
 
 CREATE TABLE t1(a int, b int);
-INSERT INTO t1 values (1, 100), (2, 200), (3, 100), (4, 200);
+INSERT INTO t1 values (1, 100), (2, 200), (3, 100), (4, 200), (5, 200);
 
 create view v1 as select a, b+1 as x from t1;