Review request for Issue #92810

There is an issue #92810 - isinstance(ABC_subclass, ...)/issubclass(ABC_subclass, ...) become very slow if lots of abstract classes are created, due to O(n^2) complexity while handling nested classes. There are 4 related PRs: additional tests for isinstance/issubclass cached and non-cached runs, no code changes https://github.com/python/cpython/pull/144941 Implementation 1 https://github.com/python/cpython/pull/131914 Implementation 2 https://github.com/python/cpython/pull/141171 Implementatio...