The previous attempt to fix this didn't preserve any attributes
but removing data-parsoid can result in a loss of wikitext formatting.
This reverts commit bdfd4b6d8f.
Bug: T207325
Change-Id: I2a38e651d17262889eddb149c72c9e08b4e56ed0
* In normal images, parse relative 'href' attributes instead of
expanding them to absolute, and parse 'resource' to keep it
identical to 'href' if they refer to the same page (including
same percent-encoding and space/underscore). This resolves Parsoid
generating |link= options for copy-pasted images (T193253).
* In gallery images stuff, prefix the 'resource' attribute with './',
same as normal images do. This causes no functional changes, but it
makes updating tests easier, and the consistency is probably good.
* Update test examples to also prefix 'resource' and relative 'href'
attributes with './', like the real Parsoid does.
Bug: T193253
Change-Id: If2d7f080d9d693568054f8311c1e1b15ca27ea5c
