QA: test2wiki redirects to https from http, causing failure

The immediate issue was to fix the bogus failure caused by
encountering https on test2wiki. See
https://wmf.ci.cloudbees.com/job/
  MobileFrontend-test2.m.wikipedia.org-linux-firefox/222/
  testReport/junit/(root)/Editor/Closing_editor__browser_button_/

In order to do that, I made some other improvements:
* Specify the URL for nonexistent page in the .feature file, not
  the page itself
* Make the test pass only if the relevant section of URL is correct
* Use "should" in Then clauses

Change-Id: If57ee26b2fc7a3c3c5cc186388b80138003e17ed
Merge "QA: test2wiki redirects to https from http, causing failure"