[issue32989] IDLE: Fix pyparse.find_good_parse_start and its bad editor call

Cheryl Sabella added the comment: > In the meanwhile, to get some idea of how well find_good_parse_start finds > good parse starts, I restarted IDLE in a console with the print still added, > loaded editor.py, and hit RETURN followed by UNDO, in various places. The > first

[issue32989] IDLE: Fix pyparse.find_good_parse_start and its bad editor call

Terry J. Reedy added the comment: I agree with limiting the scope to the None bug and the faulty call. However, we should think of the None fix as primary, and the new test thereof as the primary test. Fixing the None check exposes the call bug, which we also fix. I