Sync XHR is broken as well

XHRmonkey.user.js

/* -*- coding: UTF-8, tab-width: 2 -*- */
/*jslint indent: 2, maxlen: 80, browser: true */
// ==UserScript==
// @name        XHRmonkey test
// @namespace   greasemonkey.web-enhance.pimpmybyte.de
// @description
// @match       https://gist.github.com/mk-pmb/22b0b3d9f0f704966007347dd2168c5d
// @version     1
// @grant       GM.xmlHttpRequest
// ==/UserScript==

'use strict';
/*global GM: true */

(function resTextShim() {
  var xhr = { method: 'GET' };
  xhr.url = ('http://localhost/xhr-test.php' +
    '?host=' + location.hostname);
  xhr.synchronous = true;
  xhr.timeout = 5e3;
  'abort error load progress timeout'.replace(/\S+/g, function (evt) {
    xhr['on' + evt] = console.log.bind(console, 'GM XHR ' + evt);
  });
  console.log('GM XHR go!', xhr);
  xhr.result = GM.xmlHttpRequest(xhr);
  console.log('GM XHR result:', xhr.result);
}());