Add reproducibility test for `gzip.compress()`

The issue https://github.com/python/cpython/issues/112346 was reported, which was a failure to keep reproducibility in gzip module output from Python 3.10 to 3.11.

There was a fix discussed and rejected in https://github.com/python/cpython/issues/112346

I think it makes sense not to actually change things back, but failing to merge the PR means we also failed to add unit tests.

Can we please add a general-purpose, fragile reproducibility test for the gzip module, so that this problem does not recur?

Ex. test that the output of gzip.compress("Hello world") remains stable

def test_gzip_reproducibility():
    """If this test fails, gzip.compress does not give reproducible output. Either fix that, or document the change in What's New and change the constant 'expected' below."""
    expected = b'\x1f\x8b\x08\x00\xa2\xd2\xe1g\x02\xff\xf3H\xcd\xc9\xc9W(\xcf/\xcaI\x01\x00R\x9e\xd6\x8b\x0b\x00\x00\x00'
    assert gzip.compress(b"Hello world") == expected

    expected = 
b'\x1f\x8b\x08\x00\x00\x00\x00\x00\x02\xff\xf3H\xcd\xc9\xc9W(\xcf/\xcaI\x01\x00R\x9e\xd6\x8b\x0b\x00\x00\x00'
    assert gzip.compress(b"Hello world", mtime=0) == expected    

Linked PRs

• gh-151214

Examinez la PR liée gh-151214 et localisez les tests existants du module gzip avant de commencer. Ajoutez les vérifications de reproductibilité pour gzip.compress() présentées dans l’issue, puis confirmez que les sorties attendues restent stables et tenez compte de toute modification intentionnelle dans What's New.