D5514: test: change test's diff generation to use mdiff for nicer output

[durin42 (Augie Fackler)]

durin42 requested changes to this revision.
durin42 added a comment.
This revision now requires changes to proceed.


  (moving this off the dashboard until it gets updated)

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D5514

To: sangeet259, #hg-reviewers, durin42
Cc: pulkit, durin42, mercurial-devel