MDEV-24898: Server crashes in st_select_lex::next_select

(trivial backport to 10.2)
Add a testcase

mysql-test/r/subselect4.result

@@ -2772,3 +2772,14 @@ GROUP BY 1
 )
 1
 DROP TABLE t1;
+#
+#  MDEV-24898: Server crashes in st_select_lex::next_select / Item_subselect::is_expensive
+#  (Testcase)
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+SELECT 1 IN (SELECT (SELECT a FROM t1) AS x FROM t2 GROUP BY x);
+ERROR 21000: Subquery returns more than 1 row
+drop table t1,t2;

mysql-test/t/subselect4.test

@@ -2269,3 +2269,16 @@ SELECT
   );
 
 DROP TABLE t1;
+
+--echo #
+--echo #  MDEV-24898: Server crashes in st_select_lex::next_select / Item_subselect::is_expensive
+--echo #  (Testcase)
+--echo #
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2); # Optional, fails either way
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4); # Optional, fails either way
+
+--error ER_SUBQUERY_NO_1_ROW
+SELECT 1 IN (SELECT (SELECT a FROM t1) AS x FROM t2 GROUP BY x);
+drop table t1,t2;