Remove --harmony-for-in flag which is always false

test/mjsunit/harmony/for-in.js

-// Copyright 2015 the V8 project authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Flags: --harmony-for-in
-
-assertThrows("for (var x = 0 in {});", SyntaxError);
-assertThrows("for (const x = 0 in {});", SyntaxError);
-assertThrows("for (let x = 0 in {});", SyntaxError);

[neis, 2016/10/11 08:59:58]

Can you move the two valid cases over to the other test file?  And maybe add one
for the var case:

let n = 0;
for (var x = n++ in {});
assertEquals(1, n);

[adamk, 2016/10/11 22:14:47]

Added the failure cases to the existing test in mjsunit/for-in.js (I didn't add
another positive test case, since I think it covers the same stuff).