Rework standalone to use a synchronous loader that does not invoke Dart code

runtime/vm/port.h

 // Copyright (c) 2011, 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_PORT_H_
 #define VM_PORT_H_
 
 #include "include/dart_api.h"
 #include "vm/allocation.h"
 #include "vm/globals.h"
@@ skipping 41 matching lines @@
   static bool IsLocalPort(Dart_Port id);
 
   // Returns the owning Isolate for port 'id'.
   static Isolate* GetIsolate(Dart_Port id);
 
   static void InitOnce();
 
   static void PrintPortsForMessageHandler(MessageHandler* handler,
                                           JSONStream* stream);
 
+  static void DebugDumpForMessageHandler(MessageHandler* handler);
+
  private:
   friend class dart::PortMapTestPeer;
 
   // Mapping between port numbers and handlers.
   //
   // Free entries have id == 0 and handler == NULL. Deleted entries
   // have id == 0 and handler == deleted_entry_.
   typedef struct {
     Dart_Port port;
     MessageHandler* handler;
@@ skipping 22 matching lines @@
   static intptr_t capacity_;
   static intptr_t used_;
   static intptr_t deleted_;
 
   static Random* prng_;
 };
 
 }  // namespace dart
 
 #endif  // VM_PORT_H_