Port test_exceptions to Python 3.10

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The test.support (which sould not be used outside Python!) has been
splitted into sub-modules. Adapt test_exceptions for these changes.

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PR for the 0.29.x branch.

[scoder]

Thanks!

which sould not be used outside Python!

Note that this test file is a copy of the CPython test module that was made to assure compatibility. It's not really used outside of CPython, is it? :)

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I forward ported this change to the master branch: #4047

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Note that this test file is a copy of the CPython test module that was made to assure compatibility. It's not really used outside of CPython, is it? :)

Ah, I didn't notice. I was just reference to the note in the test documentation:

The test package is meant for internal use by Python only. It is documented for the benefit of the core developers of Python. Any use of this package outside of Python’s standard library is discouraged as code mentioned here can change or be removed without notice between releases of Python.

https://docs.python.org/dev/library/test.html