Update unittest to new package layout.

pkg/intl/test/intl_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('intl_test');
 
+// TODO(rnystrom): Use "package:" URL (#4968).
 #import('../intl.dart');
-#import('../../unittest/unittest.dart');
+#import('../../unittest/lib/unittest.dart');
 #import('../date_symbol_data_local.dart');
 
 main() {
   test("Locale setting doesn't verify the core locale", () {
       var de = new Intl('de_DE');
       expect(de.locale, equals('de_DE'));
   });
 
   test('DateFormat creation does verify the locale', (){
     // TODO(alanknight): We need to make the locale verification be on a per
     // usage basis rather than once for the entire Intl object. The set of
     // locales covered for messages may be different from that for date
     // formatting.
     initializeDateFormatting('de_DE', null).then((_) {
       var de = new Intl('de_DE');
       var format = de.date().add_d();
       expect(format.locale, equals('de'));
      });
   });
 }