Move unittest from lib to pkg.

tests/html/localstorage_test.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('LocalStorageTest');
-#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();
 
   void testWithLocalStorage(String name, fn()) {
     test(name, () {
       window.localStorage['key1'] = 'val1';
       window.localStorage['key2'] = 'val2';
       window.localStorage['key3'] = 'val3';
@@ skipping 82 matching lines @@
     window.localStorage.clear();
     Expect.equals(0, window.localStorage.length);
   });
 
   testWithLocalStorage('isEmpty', () {
     Expect.isFalse(window.localStorage.isEmpty());
     window.localStorage.clear();
     Expect.isTrue(window.localStorage.isEmpty());
   });
 }