Fix wrong initializer order -- not caught on mac build because mac

runtime/vm/thread_pool.h

 // 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.
 
 #ifndef VM_THREAD_POOL_H_
 #define VM_THREAD_POOL_H_
 
 #include "vm/thread.h"
 
 namespace dart {
@@ skipping 59 matching lines @@
     bool IsDone() const { return pool_ == NULL; }
 
     // Fields owned by Worker.
     Monitor monitor_;
     ThreadPool* pool_;
     Task* task_;
 
     // Fields owned by ThreadPool.  Workers should not look at these
     // directly.  It's like looking at the sun.
     bool owned_;         // Protected by ThreadPool::mutex_
+    Worker* all_next_;   // Protected by ThreadPool::mutex_
     Worker* idle_next_;  // Protected by ThreadPool::mutex_
-    Worker* all_next_;   // Protected by ThreadPool::mutex_
 
     DISALLOW_COPY_AND_ASSIGN(Worker);
   };
 
   void Shutdown();
 
   // Expensive.  Use only in assertions.
   bool IsIdle(Worker* worker);
 
   bool RemoveWorkerFromIdleList(Worker* worker);
@@ skipping 14 matching lines @@
 
   static Monitor* exit_monitor_;  // Used only in testing.
   static int* exit_count_;        // Used only in testing.
 
   DISALLOW_COPY_AND_ASSIGN(ThreadPool);
 };
 
 }  // namespace dart
 
 #endif  // VM_THREAD_POOL_H_