Remove the `__dict__` and `__weakref__` descriptors from the original class when creating a dataclass from it. An interesting hack, but more localized in scope than gh-135230. This may be a breaking change if people intentionally keep the original class around when using `@dataclass(slots=True)`, and then use `__dict__` or `__weakref__` on the original class. Co-authored-by: Alyssa Coghlan <ncoghlan@gmail.com> Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>