fixup! revision: create mark_trees_uninteresting_dense()

This was a preparatory commit for the path-walk API, which has since
been upstreamed into v2.54.0. During the merging-rebase, the code
changes this commit introduced were already present in the new base,
leaving it empty. Drop it.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho