Use ExitProcess on Windows.

runtime/bin/process.cc

 // Copyright (c) 2013, 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 "bin/dartutils.h"
 #include "bin/dbg_connection.h"
 #include "bin/eventhandler.h"
 #include "bin/io_buffer.h"
 #include "bin/log.h"
 #include "bin/platform.h"
@@ skipping 255 matching lines @@
     // Note that this dependency crosses logical project boundaries by making
     // the dart:io implementation depend upon the standalone VM's legacy debug
     // protocol. This breaks projects which want to use our dart:io
     // implementation. Because the protocol is going away shortly, it's
     // reasonable to leave it behind a #ifdef that is only enabled for the
     // standalone VM for now.
     DebuggerConnectionHandler::StopHandler();
 #endif
     EventHandler::Stop();
   }
-  exit(static_cast<int>(status));
+  Platform::Exit(static_cast<int>(status));
 }
 
 
 void FUNCTION_NAME(Process_SetExitCode)(Dart_NativeArguments args) {
   int64_t status = 0;
   // Ignore result if passing invalid argument and just set exit code to 0.
   DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 0), &status);
   Process::SetGlobalExitCode(status);
 }
 
@@ skipping 104 matching lines @@
     free(const_cast<char*>(system_string));
     Dart_PropagateError(result);
   }
   memmove(buffer, system_string, system_len);
   free(const_cast<char*>(system_string));
   Dart_SetReturnValue(args, external_array);
 }
 
 }  // namespace bin
 }  // namespace dart