Update unittest to new package layout.

tests/html/htmloptionscollection_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('HTMLOptionsCollectionTest');
-#import('../../pkg/unittest/unittest.dart');
-#import('../../pkg/unittest/html_config.dart');
+#import('../../pkg/unittest/lib/unittest.dart');
+#import('../../pkg/unittest/lib/html_config.dart');
 #import('dart:html');
 
 main() {
   useHtmlConfiguration();
 
   test('indexedAccessTest', () {
     // FIXME: we need some massaging to dart:html to enable HTMLOptionsCollection.add
     // and hence programatic building of collection.
     final selectElement = new Element.html('''
       <select>
@@ skipping 11 matching lines @@
     expect(optionsCollection[1].text, equals('Option1'));
     expect(optionsCollection[2].text, equals('Option2'));
 
     expect(() { optionsCollection[0] = 1; }, throws);
 
     optionsCollection[0] = new OptionElement(value: '42', data: 'Option42');
     expect(optionsCollection[0].value, equals('42'));
     expect(optionsCollection[0].text, equals('Option42'));
   });
 }