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

runtime/vm/debugger_api_impl_test.cc

-// 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 "include/dart_debugger_api.h"
-
-#include "vm/assert.h"
+#include "platform/assert.h"
 #include "vm/unit_test.h"
 
 namespace dart {
 
 #if defined(TARGET_ARCH_IA32)  // Only ia32 can run execution tests.
 
 
 static bool breakpoint_hit = false;
 
 static const bool verbose = false;
@@ skipping 60 matching lines @@
                            Dart_NewString("main"),
                            0,
                            NULL);
   EXPECT(!Dart_IsError(retval));
   EXPECT(breakpoint_hit == true);
 }
 
 #endif  // TARGET_ARCH_IA32.
 
 }  // namespace dart