bpo-39829: Fix `__len__()` is called twice in list() constructor (GH-31816)

(cherry picked from commit 2153daf0a02a598ed5df93f2f224c1ab2a2cca0d)

This patch fixes gh-87740 too.

Co-authored-by: Crowthebird <78076854+thatbirdguythatuknownot@users.noreply.github.com>
3 files changed