Merge branch 'jk/prune-with-bitmap-fix'

Merge branch 'jk/prune-with-bitmap-fix'

When the reachability bitmap is in effect, the "do not lose
recently created objects and those that are reachable from them"
safety to protect us from races were disabled by mistake, which has
been corrected.

* jk/prune-with-bitmap-fix:
  prune: save reachable-from-recent objects with bitmaps
  pack-bitmap: clean up include_check after use