Merge branch 'td/ls-files-pathspec-prefilter'

`git ls-files --modified` and `git ls-files --deleted` have been
optimized to filter with pathspec before calling lstat() when there is
only a single pathspec item, avoiding unnecessary filesystem access
for entries that will not be shown.

* td/ls-files-pathspec-prefilter:
  ls-files: filter pathspec before lstat