[3.9] bpo-41218: Only mark async code with CO_COROUTINE. (GH-21357) (GH-21362)

3.8.3 had a regression where compiling with
ast.PyCF_ALLOW_TOP_LEVEL_AWAIT woudl agressively mark things are
coroutine even if there were not.
(cherry picked from commit bd46174)

Co-authored-by: Matthias Bussonnier <bussonniermatthias@gmail.com>

Co-authored-by: Matthias Bussonnier <bussonniermatthias@gmail.com>
3 files changed