[3.13] gh-140482: Preserve and restore `stty echo` as a test environment (GH-140519) (#140563)

gh-140482: Preserve and restore `stty echo` as a test environment (GH-140519)
(cherry picked from commit b3c713a0af5f5c4b5704d8019a893a1b70eba941)


gh-140482: Restore `stty echo` as a test environment

Co-authored-by: Barry Warsaw <barry@python.org>