test rename overhaul: step 8 - language tests

tests/language/factory4_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.
 
 interface Link<T> default LinkFactory {
   Link.create();
 }
 
 class A<T> { }
 
 class LinkFactory<T> extends A<T> {
   factory Link.create() {
     return null;
   }
 }
 
 main() {
   var a = new Link<int>.create();
 }