pkg/intl test cleanup

pkg/intl/test/date_time_format_uninitialized_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.
 
 /**
  * Tests date formatting and parsing using locale data read from the
  * local file system.
  */
 library date_time_format_file_test;
 
-import 'package:intl/intl.dart';
-import 'package:intl/date_symbol_data_local.dart';
 import 'date_time_format_test_core.dart';
-import 'package:unittest/unittest.dart';
 
 main() {
-  runDateTests(['en_US']);
+  runDateTests(() => ['en_US']);
 }