Fixing a bunch of dartc errors in dart:html tests.

tests/html/util.dart

 // 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.
 
+library test.html.util;
+
+import 'dart:html';
+import '../../pkg/unittest/lib/unittest.dart';
+
 void expectUnsupported(f) => expect(f, throwsUnsupportedError);
 
 void expectEmptyRect(ClientRect rect) {
   expect(rect.bottom, isZero);
   expect(rect.top, isZero);
   expect(rect.left, isZero);
   expect(rect.right, isZero);
   expect(rect.height, isZero);
   expect(rect.width, isZero);
 }