XHR: responseURL with fragment

For whatwg/xhr#200.

Author: annevk

xhr/responseurl-fragment.any.js

@@ -0,0 +1,11 @@
+// META global=window,dedicatedworker,sharedworker
+
+async_test(t => {
+  const client = new XMLHttpRequest(),
+        url = new URL("resources/base.xml#test", location).href;
+  client.open("GET", url);
+  client.send();
+  client.onload = t.step_func_done(() => {
+    assert_equals(client.responseURL, url);
+  });
+}, "responseURL should preserve the fragment");