Fix image up-scaling for 'format unspecified' images.

Added test cases for enlarging images, based on
https://www.mediawiki.org/wiki/Help:Images#Size_and_frame
and PHP parser output.  Tweaked Parsoid to properly scale up
images where requested.

A few more selser failures are added to the blacklist because of
bug 62498.

Bug: 62501
Change-Id: I6c82d36c873d889bb1dc13ffddaa71d47ca91758