Back out 97036ab72558 which inappropriately compared turds to third parties.
1 // for-of can iterate over generator-iterators produced by generator-expressions.
9 for (var i = 0; i < 10; i++) {
11 it = (k + 1 for (k of prev));
14 var arr = [v for (v of it)];
15 assertEq(arr.join(), "11,12");