* Followup to 9a466310
* I had previously added page title info to ParserOutput as part of
6e5413b1, but while working on 9a466310, we didn't realize that.
* Removed urldecode(..) since output of Title::getPrefixedDBKey
isn't urlencoded and urldecode converts "+" into " ". A new test
ensures that edge case works properly.
* Simplify testing + add additional test to ensure title normalization
doesn't trip up the transform.
Bug: T358242
Change-Id: I9a0cb00bdf9d104a4b327d72b1ec94cf509883a2