gh-102978: Fix mock.patch function signatures for class and staticmethod decorators (#103228)

Fixes unittest.mock.patch not enforcing function signatures for methods
decorated with @classmethod or @staticmethod when patch is called with
autospec=True.

Backports: 59e0de4903c02e72b329e505fddf1ad9794928bc
Signed-off-by: Chris Withers <chris@simplistix.co.uk>
4 files changed