Cleanup/Remove Windows XP/Vista version checks from Windows sandbox code

sandbox/win/src/Wow64_64.cc

-// Copyright (c) 2011 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-// Wow64 implementation for native 64-bit Windows (in other words, never WOW).
-
-#include "sandbox/win/src/wow64.h"
-
-namespace sandbox {
-
-Wow64::Wow64(TargetProcess* child, HMODULE ntdll)
-    : child_(child), ntdll_(ntdll), dll_load_(NULL), continue_load_(NULL) {
-}
-
-Wow64::~Wow64() {
-}
-
-bool Wow64::WaitForNtdll() {
-  return true;
-}
-
-}  // namespace sandbox