[3.13] gh-123934: Fix `MagicMock` not to reset magic method return values (GH-124038) (#124231)

gh-123934: Fix `MagicMock` not to reset magic method return values (GH-124038)
(cherry picked from commit 7628f67d55cb65bad9c9266e0457e468cd7e3775)

Co-authored-by: sobolevn <mail@sobolevn.me>
3 files changed