[XHR] Rewrite layout test redirect-cross-origin-tripmine.html using Promises

Unnecessary delay is removed

Use js-test.js instead of manual logging, asserts

BUG=27569

Review URL: https://codereview.chromium.org/344533006

git-svn-id: svn://svn.chromium.org/blink/trunk@176484 bbb929c8-8fbe-4397-9dbb-9b2b20218538