Complete support for Windows TLS destructors

runtime/vm/thread_pool.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 "vm/thread_pool.h"
 
 #include "vm/flags.h"
 #include "vm/lockers.h"
 
 namespace dart {
@@ skipping 453 matching lines @@
     }
   } else {
     // This worker is going down because it was idle for too long. This case
     // is not due to a ThreadPool Shutdown. Thus, we simply delete the worker.
     // The worker's id is added to the thread pool's join list by
     // ReleaseIdleWorker, so in the case that the thread pool begins shutting
     // down immediately after returning from worker->Loop() above, we still
     // wait for the thread to exit by joining on it in Shutdown().
     delete worker;
   }
-#if defined(TARGET_OS_WINDOWS)
-  Thread::CleanUp();
-#endif
 }
 
 }  // namespace dart