MDEV-24919 Crash with subselect formed by table value constructor and

used in set function

If a subselect is formed by a table value constructor (TVC) then the
following transformation is applied at the prepare stage:
  VALUES (v1), ... (vn) => SELECT * FROM (VALUES (v1), ... (vn)) tvc_x.
The transformation is performed by the function wrap_tvc() that resets
THD::LEX::current select to the top level select of the result of the
transformation. After the call of wrap_tvc() in the function
Item_subselect::wrap_tvc_into_select() the field THD::LEX::current must be
reset to the same select as before the call. It was not done. As a result
if the subselect formed by a TVC was an argument of a set function then
an assertion was hit in the function Item_sum::check_sum_func().

Approved by Oleksandr Byelkin <sanja@mariadb.com>

mysql-test/main/table_value_constr.result

@@ -2881,4 +2881,10 @@ NULL
 deallocate prepare stmt;
 drop view v1;
 drop table t1,t2,t3;
+#
+# MDEV-24919: subselect formed by TVC and used in set function
+#
+select sum((values(1)));
+sum((values(1)))
+1
 End of 10.3 tests