Bug 1463077 [wpt PR 11091] - Wait until window load before calling window.stop() in XHR test, a=testonly

Automatic update from web-platform-testsWait until window load before calling window.stop() in XHR test (#11091)

https://wpt.fyi/xhr/abort-after-stop.htm is broken in 3/4 browsers and
it appears this is because calling window.stop() causes the window
load event to never be fired, and testharness.js depends on that.

There is no harness timeout in Edge, because Edge fires the load
event. Tested with https://jsbin.com/tufepag/edit?js,console and filed
https://github.com/w3c/web-platform-tests/issues/11090 for the lack of
tests for this.
--

wpt-commits: aa091291c045c0c53706d8541290e496fd8f4dd8
wpt-pr: 11091

testing/web-platform/meta/MANIFEST.json

@@ -621910,7 +621910,7 @@
    "testharness"
   ],
   "xhr/abort-after-stop.htm": [
-   "3feb39f2451afa624771437337c669865fac29b5",
+   "8822f48665a569b37bde50995c48687825672a50",
    "testharness"
   ],
   "xhr/abort-after-timeout.htm": [

testing/web-platform/tests/xhr/abort-after-stop.htm

@@ -10,7 +10,7 @@
     <div id="log"></div>
     <script>
       var test = async_test();
-      test.step(function() {
+      window.onload = test.step_func(function() {
         var client = new XMLHttpRequest();
         var abortFired = false;
         client.onabort = test.step_func(function (e) {