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

runtime/vm/isolate_win.cc

Index: runtime/vm/isolate_win.cc
diff --git a/runtime/vm/isolate_win.cc b/runtime/vm/isolate_win.cc
index 2170d8b1762e6d23b79c545f1e7152e67053e8dc..80af81016fcc6018df3f817739d46c37ccea75ff 100644
--- a/runtime/vm/isolate_win.cc
+++ b/runtime/vm/isolate_win.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 "vm/assert.h"
-#include "vm/globals.h"
 #include "vm/isolate.h"
 
+#include "platform/assert.h"
+#include "vm/globals.h"
+
 namespace dart {
 
 DWORD isolate_key = TLS_OUT_OF_INDEXES;