[3.13] gh-131113: Fix data race in dict.popitem() (gh-131115) (#131119)

The clearing of the key, hash, and value need to use atomic operations
to avoid a data race with concurrent read operations.
(cherry picked from commit c00ac578241b3213ceb79c1f32bc83ea471f02da)

Co-authored-by: Sam Gross <colesbury@gmail.com>