Revert of [parser] Fix scopes in rewriting of for-of and destructuring assignments.

test/mjsunit/regress/regress-5648.js

-// Copyright 2016 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.
-
-
-var iter = {}
-iter[Symbol.iterator] = () => ({
-  next: () => ({}),
-  return: () => {throw 666}
-});
-
-
-function* foo() {
-  for (let x of iter) {throw 42}
-}
-assertThrowsEquals(() => foo().next(), 42);
-
-
-function* bar() {
-  let x;
-  { let gaga = () => {x};
-    [[x]] = iter;
-  }
-}
-assertThrows(() => bar().next(), TypeError);
-
-
-function baz() {
-  let x;
-  { let gaga = () => {x};
-    let gugu = () => {gaga};
-    [[x]] = iter;
-  }
-}
-assertThrows(baz, TypeError);