The wiki part of the link is lost in the link index table

In the refactoring for XWIKI-19352 the wiki part of cross wiki links was lost, so all links in the links tables now appear to target documents in the current wiki.

The use of compact serializer (which keep the wiki part when it's different from the current one) was replaced by the local serializer (which always remove the wiki part).

It's a lot less visible in XWiki 14.8+ since that table is not really used anymore in XWiki Standard and is just kept as a retro temporary compatibility measure.