gh-99155: Fix NormalDist pickle with 0 and 1 protocols

[sobolevn]

With new tests, but before my Lib/statistics.py change:

======================================================================
ERROR: test_pickle (test.test_statistics.TestNormalDistC.test_pickle) (proto=0)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/sobolev/Desktop/cpython/Lib/test/test_statistics.py", line 3017, in test_pickle
    pickled = pickle.loads(pickle.dumps(nd, protocol=proto))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/sobolev/Desktop/cpython/Lib/copyreg.py", line 94, in _reduce_ex
    raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining __getstate__ cannot be pickled

======================================================================
ERROR: test_pickle (test.test_statistics.TestNormalDistC.test_pickle) (proto=1)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/sobolev/Desktop/cpython/Lib/test/test_statistics.py", line 3017, in test_pickle
    pickled = pickle.loads(pickle.dumps(nd, protocol=proto))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/sobolev/Desktop/cpython/Lib/copyreg.py", line 94, in _reduce_ex
    raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining __getstate__ cannot be pickled

======================================================================
ERROR: test_pickle (test.test_statistics.TestNormalDistPython.test_pickle) (proto=0)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/sobolev/Desktop/cpython/Lib/test/test_statistics.py", line 3017, in test_pickle
    pickled = pickle.loads(pickle.dumps(nd, protocol=proto))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/sobolev/Desktop/cpython/Lib/copyreg.py", line 94, in _reduce_ex
    raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining __getstate__ cannot be pickled

======================================================================
ERROR: test_pickle (test.test_statistics.TestNormalDistPython.test_pickle) (proto=1)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/sobolev/Desktop/cpython/Lib/test/test_statistics.py", line 3017, in test_pickle
    pickled = pickle.loads(pickle.dumps(nd, protocol=proto))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/sobolev/Desktop/cpython/Lib/copyreg.py", line 94, in _reduce_ex
    raise TypeError("a class that defines __slots__ without "
TypeError: a class that defines __slots__ without defining __getstate__ cannot be pickled

----------------------------------------------------------------------
Ran 2 tests in 0.007s

• Issue: statistics.NormalDist fails to be pickled with 0 and 1 protocols #99155

[miss-islington]

Thanks @sobolevn for the PR, and @rhettinger for merging it 🌮🎉.. I'm working now to backport this PR to: 3.10, 3.11.
🐍🍒⛏🤖

[miss-islington]

Sorry, @sobolevn and @rhettinger, I could not cleanly backport this to 3.11 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker d7a00f1e8eee05fc5ae97ea1ef0615feefce887b 3.11

[miss-islington]

Sorry, @sobolevn and @rhettinger, I could not cleanly backport this to 3.10 due to a conflict.
Please backport using cherry_picker on command line.
cherry_picker d7a00f1e8eee05fc5ae97ea1ef0615feefce887b 3.10

[bedevere-bot]

GH-99188 is a backport of this pull request to the 3.11 branch.