Implementing timeout support for XHR

LayoutTests/http/tests/xmlhttprequest/timeout/xmlhttprequest-timeout.js

 /* Test imported from Alex Vincent's XHR2 timeout tests, written for Mozilla.
    https://hg.mozilla.org/mozilla-central/file/tip/content/base/test/
    Released into the public domain, according to
    https://bugzilla.mozilla.org/show_bug.cgi?id=525816#c86
 */
 
 /* Notes:
    - All times are expressed in milliseconds in this test suite.
    - Test harness code is at the end of this file.
    - We generate only one request at a time, to avoid overloading the HTTP
    request handlers.
  */
 
 var TIME_NORMAL_LOAD = 1000;
 var TIME_LATE_TIMEOUT = 800;
 var TIME_XHR_LOAD = 600;
 var TIME_REGULAR_TIMEOUT = 400;
 var TIME_SYNC_TIMEOUT = 200;
 var TIME_DELAY = 200;
 
 /*
  * This should point to a resource that responds after a delay of TIME_XHR_LOAD milliseconds.
  */
-var STALLED_REQUEST_URL = "/resources/load-and-stall.cgi?name=../../../http/tests/xmlhttprequest/timeout/xmlhttprequest-timeout.js&stallFor=" + TIME_XHR_LOAD/1000 + "&stallAt=0&mimeType=text/plain";
+var STALLED_REQUEST_URL = "/resources/load-and-stall.php?name=../../../http/tests/xmlhttprequest/timeout/xmlhttprequest-timeout.js&stallFor=" + TIME_XHR_LOAD/1000 + "&stallAt=0&mimeType=text/plain";
 
 var inWorker = false;
 try {
   inWorker = !(self instanceof Window);
 } catch (e) {
   inWorker = true;
 }
 
 function message(obj) {
   if (inWorker)
@@ skipping 331 matching lines @@
     }
   }
 };
 
 self.addEventListener("message", function (event) {
   if (event.data.type == "start") {
     TestRequests = TestRequestGroups[event.data.group];
     TestCounter.next();
   }
 });