Move assert.h/assert.cc from runtime/vm to runtime/platform

runtime/bin/directory.cc

Index: runtime/bin/directory.cc
diff --git a/runtime/bin/directory.cc b/runtime/bin/directory.cc
index 3c9fc4d26800e536c3e6b903b7f2682ff3618267..739c43aaaaef8b64b94667a4877f3ab076b0fbf3 100644
--- a/runtime/bin/directory.cc
+++ b/runtime/bin/directory.cc
@@ -1,11 +1,12 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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 "bin/dartutils.h"
 #include "bin/directory.h"
 
+#include "bin/dartutils.h"
 #include "include/dart_api.h"
+#include "platform/assert.h"
 
 static intptr_t GetHandlerPort(Dart_Handle handle) {
   if (Dart_IsNull(handle)) {