deepcopy memoryview raises TypeError

Bug report

Calling deepcopy on a memoryview raises a TypeError, this looks similar to bug 82474 https://github.com/python/cpython/issues/82474

This also breaks BinaryField when using Django Polymorphic

https://github.com/django-polymorphic/django-polymorphic/issues/524
Your environment

• CPython versions tested on: 3.8, 3.10
• Operating system and architecture: Ubuntu 21.10

>>> a = memoryview(b'123')
>>> from copy import deepcopy
>>> deepcopy(a)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python3.10/copy.py", line 161, in deepcopy
    rv = reductor(4)
TypeError: cannot pickle 'memoryview' object

从 traceback 显示的 Lib/copy.py 中的 deepcopy 路径开始，并在受支持的 CPython 版本上使用 memoryview 示例重现该故障。检查相关的 issue 82474，并确定针对 memoryview 的预期 deepcopy 行为；done 应包含对所报告案例的 coverage，并且 deepcopy 不应产生 TypeError。