Update dart2js_foreign suite as we now validate annotations.

dart/tests/compiler/dart2js_foreign/native_window2_test.dart

Index: dart/tests/compiler/dart2js_foreign/native_window2_test.dart
diff --git a/dart/tests/compiler/dart2js_foreign/native_window2_test.dart b/dart/tests/compiler/dart2js_foreign/native_window2_test.dart
index a9e14798e6ec303d9ead7a3788f2226f40ad8061..414ede5fed62d7d8454a839ff446b76c99401085 100644
--- a/dart/tests/compiler/dart2js_foreign/native_window2_test.dart
+++ b/dart/tests/compiler/dart2js_foreign/native_window2_test.dart
@@ -2,13 +2,15 @@
 // 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.
 
+import 'native_metadata.dart';
+
 interface Window {
   final int document;
 }
 
 // Defining this global object makes Frog eager on optimizing
 // call sites where the receiver is typed 'Window'.
-@native("@*DOMWindow")
+@Native("@*DOMWindow")
 class _DOMWindowJs implements Window  {
   final int document;
 }