bpo-44806: Fix __init__ in subclasses of protocols (GH-27545)


Non-protocol subclasses of protocol ignore now the __init__ method
inherited from protocol base classes.
(cherry picked from commit 043cd60abed09edddc7185bcf7d039771acc734d)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
3 files changed