Don't ignore data-parsoid in DOMDiff, attempt 2

This is a fixed version of Subbu's 2c45ade9723ea06f538ff5b2255dcb5d1fbbd601,
which I reverted due to https://bugzilla.wikimedia.org/show_bug.cgi?id=48018.

* In VE, sometimes wrappers get moved around without their content
  which can cause p-wrapper of deleted content to be used on
  identical undeleted content.  Since the identical undeleted content
  is marked as unchanged, selser tries to emit use dsr from its wrapper
  to emit original src, but the wrapper is not the right one and leads
  selser to emit more/less text depending on how VE manipulated the
  wrappers.

  Discovered via: /mnt/bugs/2013-05-01T09:43:14.960Z-Reverse_innovation

* Unrelated fixes: Updated debugging output in DOMDiff.

* Tested via:

node parse --html2wt --selser --domdiff domdiff.diff.html --oldtextfile wt < editedHtml

   which emitted duplicate text before this patch and emits correct
   text after this patch.

* parserTests results:
  - Inexplicably, this patch causes selser to reuse more original
    source fragments on parserTests.

  -  Leads to one selser test passing (which passes in wt2wt mode),
     and 3 selser tests failing (all of which fail in wt2wt mode as well).

  -  Updated blacklist.

Change-Id: Ib0c781568d83b59c36acf47254e8dd9a6a30034f
Merge "Don't ignore data-parsoid in DOMDiff, attempt 2"