Revert "Hack around TLS destructors firing after the process exits"

runtime/bin/platform_win.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "platform/globals.h"
 #if defined(TARGET_OS_WINDOWS)
 
 #include "bin/file.h"
 #include "bin/platform.h"
 #include "bin/log.h"
 #include "bin/socket.h"
 #include "bin/utils.h"
 #include "bin/utils_win.h"
 
 
 namespace dart {
-
-// Defined in vm/os_thread_win.cc
-extern bool private_flag_windows_run_tls_destructors;
-
 namespace bin {
 
 bool Platform::Initialize() {
   // Nothing to do on Windows.
   return true;
 }
 
 
 int Platform::NumberOfProcessors() {
   SYSTEM_INFO info;
@@ skipping 72 matching lines @@
   }
   char* path = StringUtilsWin::WideToUtf8(tmp_buffer);
   free(tmp_buffer);
   // Return the canonical path as the returned path might contain symlinks.
   char* canon_path = File::GetCanonicalPath(path);
   free(path);
   return canon_path;
 }
 
 void Platform::Exit(int exit_code) {
-  ::dart::private_flag_windows_run_tls_destructors = false;
   // On Windows we use ExitProcess so that threads can't clobber the exit_code.
   // See: https://code.google.com/p/nativeclient/issues/detail?id=2870
   ::ExitProcess(exit_code);
 }
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_WINDOWS)