Throttle intl file tests

pkg/intl/test/date_time_format_file_test_stub.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 '../lib/intl.dart';
 import '../lib/date_symbol_data_file.dart';
 import 'dart:io';
 import 'date_time_format_test_core.dart';
 import 'data_directory.dart';
 import '../../../pkg/unittest/lib/unittest.dart';
 
 runWith([Function getSubset]) {
   // Initialize one locale just so we know what the list is.
   test('Run all date formatting tests with locales from files', () {
     initializeDateFormatting("en_US", dataDirectory).then(
         expectAsync1((_) => runEverything(getSubset)));
   });
 }
 
 void runEverything(Function getSubset) {
-  // Initialize all locales and wait for them to finish before running tests.
-  var futures = DateFormat.allLocalesWithSymbols().map(
+  // Initialize all locales sequentially before running tests. Be sure not
+  // to do it in parallel or we can run into ulimit problems on fast machines.
+  var futureList = Futures.forEach(DateFormat.allLocalesWithSymbols(),
       (locale) => initializeDateFormatting(locale, dataDirectory));
+
   test('Run all date formatting tests nested test', () {
-    Futures.wait(futures).then(
+    futureList.then(
         expectAsync1((results) => runDateTests(getSubset())));
   });
 }