Back out 97036ab72558 which inappropriately compared turds to third parties.
1 // for-of consults Array.prototype when it encounters a hole.
3 Array.prototype[1] = 'peek';
5 for (var x of [0, , 2, 3])
7 assertEq(log[1], 'peek');
8 assertEq(log.join(), "0,peek,2,3");