Order by with loose index scan input results in a failed assert during the join cleanup phase

The following test case (based on Bug #32268: Indexed queries give bogus MIN and MAX results, from group_min_max.test) leads to a crash during the cleanup phase:

CREATE TABLE t1 (a INT, b INT);
INSERT INTO t1 (a, b) VALUES (1,1), (1,2), (1,3);
INSERT INTO t1 SELECT a + 1, b FROM t1;
INSERT INTO t1 SELECT a + 2, b FROM t1;

CREATE INDEX break_it ON t1 (a, b);

SELECT distinct a, b FROM t1 where a = '3' ORDER BY b;