bpo-39595: Improve zipfile.Path performance (#18406)

* Improve zipfile.Path performance on zipfiles with a large number of entries.

* 📜🤖 Added by blurb_it.

* Add bpo to blurb

* Sync with importlib_metadata 1.5 (6fe70ca)

* Update blurb.

* Remove compatibility code

* Add stubs module, omitted from earlier commit

Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>