Bug 1884868 - adjust testCancelWaitForRedirect(). r=freaktechnik

It looks like the close Cancellation/rejection happens earlier now.

Differential Revision: https://phabricator.services.mozilla.com/D204477

--HG--
extra : amend_source : 846bd45d642f7c8b938a9a5961181c7440449073

mail/components/im/test/browser/browser_browserRequest.js

@@ -81,10 +81,9 @@ add_task(async function testCancelWaitForRedirect() {
 
   await new Promise(resolve => setTimeout(resolve));
 
+  await BrowserTestUtils.closeWindow(requestWindow);
   const closeEvent = new Event("close");
   requestWindow.dispatchEvent(closeEvent);
-  await BrowserTestUtils.closeWindow(requestWindow);
-
   try {
     await request;
     ok(false, "request should be rejected");