Updated mediawiki/extensions
Project: mediawiki/extensions/Parsoid  bf24f8c6e94563062e6c7544ed09486120044102
null
Selective serializer and DOMDiff fixes

Fixing the async code paths not tested in parserTests. Also a mix of code
fixes in DOMDiff, new methods in DOMUtils and minor tweaks in
WikitextSerializer.

312 additional (vs. master) selser tests are green with this patch.

Change-Id: If95092f86ad82329139582a6a5cb2d6d337cbaf0