Fix RT-testing regressions caused by 2c30cbfa

* #REDIRECT [[Main_Page]] was being RT-ed back in canonical
  form #REDIRECT [[Main Page]]. This showed up in RT testing
  where enwiki:Elizabeth_Truman and a bunch of other pages
  showing dirty diffs.

* This patch fixes that breakage.

* Added new tests to capture additional redirect variants.

Change-Id: I5d0020e774d8a2a92be11f1fcf9a08895bce8d65
Merge "Fix RT-testing regressions caused by 2c30cbfa"