Revert "Simplify MWTidy"

This is broken, for reasons indicated in
<https://gerrit.wikimedia.org/r/#/c/180384/>. It was broken before, but I made
it more broken. So revert for now, and I'll give this another stab.

Change-Id: I7e67a61f7d6370f90487be6470bebe1449432a4c