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

runtime/vm/ast_printer_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 "vm/assert.h"
+#include "platform/assert.h"
 #include "vm/ast_printer.h"
 #include "vm/heap.h"
 #include "vm/isolate.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/unit_test.h"
 
 namespace dart {
 
 TEST_CASE(AstPrinter) {
@@ skipping 14 matching lines @@
   AstPrinter::PrintNode(new ReturnNode(kPos));
 
   AstPrinter::PrintNode(new BinaryOpNode(kPos,
                           Token::kADD,
                           new LiteralNode(kPos, Smi::ZoneHandle(Smi::New(3))),
                           new LiteralNode(kPos, Smi::ZoneHandle(Smi::New(5)))));
   AstPrinter::PrintNode(new UnaryOpNode(kPos, Token::kSUB, ll));
 }
 
 }  // namespace dart