Revert "Do all of Cite's real work during unstrip" and followup

This reverts commits 944b24542827f827cdfb8646f1c2e87aeb929b65
and fa7be37d15fa6afd9bd76326e52b7503fd8ada32.

These resulted in too many new exciting behaviors for the improvement
of nested refs behavior to be worth it. We should try again later.

Also, use Parser::MARKER_PREFIX instead of $parser->uniqPrefix()
which has been deprecated in the meantime by 12571bde.

Fixes T101390, fixes T100477. Reopens T22707, reopens T18330.

Bug: T100477
Bug: T101390
Change-Id: I1a71854cf24e85697ab171be43eeec9054bc504c
(cherry picked from commit 3f30e08d7752964d62a0ede2b9a485186d469710)