Merge branch 'ds/path-walk-repack-fix' into maint-2.51

"git repack --path-walk" lost objects in some corner cases, which
has been corrected.
cf. <CABPp-BHFxxGrqKc0m==TjQNjDGdO=H5Rf6EFsf2nfE1=TuraOQ@mail.gmail.com>

* ds/path-walk-repack-fix:
  path-walk: create initializer for path lists
  path-walk: fix setup of pending objects