Split date formatting tests in two to avoid timeouts

pkg/intl/test/date_time_format_file_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_test');
-
-#import('../date_format.dart');
-#import('../date_symbol_data_file.dart');
-#import('dart:io');
-#import('date_time_format_test_core.dart');
-#import('data_directory.dart');
-
-main() {
-  // Initialize one locale just so we know what the list is.
-  initializeDateFormatting("en_US", dataDirectory).then(runEverything);
-}
-
-void runEverything(_) {
-  // Initialize all locales and wait for them to finish before running tests.
-  var futures = DateFormat.allLocalesWithSymbols().map(
-      (locale) => initializeDateFormatting(locale, dataDirectory));
-  Futures.wait(futures).then((results) => runDateTests());
-}