Don't use __getstate__ for pickling for objects with a custom __reduce__.

[robertwb]

This fixes #33137

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[github-actions]

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[liferoad]

are we sure this works?

class MyClass:
    def __init__(self, value):
        self.value = value

    def __reduce__(self):
        return (self.__class__, (self.value,))

tt = MyClass(1)
print(object.__reduce__ == type(tt).__reduce__)

This also returns False. I might misunderstand how this works.

[robertwb]

We want this to return False as MyClass has a custom __reduce__ method (meaning relying on __set/getstate__ is not safe).

[liferoad]

I see what you mean now. Thanks. Better fix than my hack.

[robertwb]

Well, thanks goes to you for hunting down the root cause; it was not obvious at all what was going on here :). I'll merge once tests pass.

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