Let %autoreload work on modules with frozen dataclasses
Let %autoreload work on modules with frozen dataclasses

See Issue #12411 and Issue #12185.
The problem is that a frozen `dataclasses.dataclass` overrides the `__setattr__()` method, so updating its `__class__` member requires going through the base `object` class.  This seems to fix the problem.
ipython/ipython,ipython/ipython