[3.11] gh-113269: IDLE - Fix test_editor hang (macOS) (GH-113271) (#113273)

gh-113269: IDLE - Fix test_editor hang (macOS) (GH-113271)

Hangs on installed 3.13.0a2 on macOS Catalina.
Behavior on installed 3.12.1 and 3.11.7 is unknown.
(cherry picked from commit fa9ba02353d79632983b9fe24da851894877e342)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>