LP:784297 - Failure in multi-update that uses a derived table.

When trying to execute the test test case of bug #52157 from mysql-test/t/multi_update.test on the LP tree
maria-5.3-mwl106 you get:

MariaDB [test]> CREATE FUNCTION f1 () RETURNS BLOB RETURN 1;
Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> CREATE TABLE t1 (f1 DATE);
Query OK, 0 rows affected (0.01 sec)

MariaDB [test]> INSERT INTO t1 VALUES('2001-01-01');
Query OK, 1 row affected (0.00 sec)

MariaDB [test]> UPDATE (SELECT 1 FROM t1 WHERE f1 = (SELECT f1() FROM t1)) x, t1 SET f1 = 1;
ERROR 1093 (HY000): You can't specify target table 'x' for update in FROM clause

Yet, on the 5.3 tree the last statement works fine:

MariaDB [test]> UPDATE (SELECT 1 FROM t1 WHERE f1 = (SELECT f1() FROM t1)) x, t1 SET f1 = 1;
Query OK, 0 rows affected, 1 warning (0.01 sec)
Rows matched: 0 Changed: 0 Warnings: 0