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

runtime/vm/virtual_memory_win.cc

Index: runtime/vm/virtual_memory_win.cc
diff --git a/runtime/vm/virtual_memory_win.cc b/runtime/vm/virtual_memory_win.cc
index 96c285f9d870ffb6186ec55767c4e7c5da097610..a3e9117d229692a59dbfce3b0739200ff75f7ac6 100644
--- a/runtime/vm/virtual_memory_win.cc
+++ b/runtime/vm/virtual_memory_win.cc
@@ -1,9 +1,10 @@
-// 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/virtual_memory.h"
-#include "vm/assert.h"
+
+#include "platform/assert.h"
 
 namespace dart {