Move unittest from lib to pkg.

tests/html/cssstyledeclaration_test.dart

 // Copyright (c) 2011, 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('CSSStyleDeclarationTest');
-#import('../../lib/unittest/unittest.dart');
-#import('../../lib/unittest/html_config.dart');
+#import('../../pkg/unittest/unittest.dart');
+#import('../../pkg/unittest/html_config.dart');
 #import('dart:html');
 
 main() {
   useHtmlConfiguration();
 
   createTestStyle() {
     return new CSSStyleDeclaration.css("""
       color: blue;
       width: 2px !important;
       -webkit-transform: rotate(90deg);
@@ skipping 51 matching lines @@
     expect(style.width, equals("2px"));
     expect(style.transform, equals("rotate(90deg)"));
 
     style.color = "red";
     style.transform = "translate(10px, 20px)";
     expect(style.cssText,
       equals("color: red; width: 2px !important;"
              " -webkit-transform: translate(10px, 20px); "));
   });
 }