Pass Redirect status higher than 307 through to the user

tests/html/xhr_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 XHRTest;
 import 'dart:async';
 import 'dart:convert';
 import 'dart:html';
 import 'dart:typed_data';
 import 'package:unittest/html_individual_config.dart';
@@ skipping 46 matching lines @@
       HttpRequest xhr = new HttpRequest();
       xhr.open("GET", "NonExistingFile", async: true);
       xhr.onReadyStateChange.listen(expectAsyncUntil((event) {
         if (xhr.readyState == HttpRequest.DONE) {
           validate404(xhr);
         }
       }, () => xhr.readyState == HttpRequest.DONE));
       xhr.send();
     });
 
-    test('XHR file', () {
+    test('XHR_file', () {
       var loadEndCalled = false;
 
       var xhr = new HttpRequest();
       xhr.open('GET', url, async: true);
       xhr.onReadyStateChange.listen(expectAsyncUntil((e) {
         if (xhr.readyState == HttpRequest.DONE) {
           validate200Response(xhr);
 
           Timer.run(expectAsync(() {
             expect(loadEndCalled, HttpRequest.supportsLoadEndEvent);
@@ skipping 172 matching lines @@
         (xhr) {
           var contentTypeHeader = xhr.responseHeaders['content-type'];
           expect(contentTypeHeader, isNotNull);
           // Should be like: 'text/plain; charset=utf-8'
           expect(contentTypeHeader.contains('text/plain'), isTrue);
           expect(contentTypeHeader.contains('charset=utf-8'), isTrue);
         });
     });
   });
 }