gh-102491: Remove IronPython version check in sys_version

[eendebakpt]

The platform module contains various version checks for systems such as cpython and ironpython. The file also contains a specfic case for ironpython which can be removed (see IronLanguages/ironpython3#1667)

Removing the check improves the import speed as it avoids the compilation of a two regular expressions.

%timeit _ironpython26_sys_version_parser = re.compile(r'([\d.]+)\s*' r'\(IronPython\s*' r'[\d.]+\s*' r'\(([\d.]+)\) on ([\w.]+ [\d.]+(?: \(\d+-bit\))?)\)' ) 383 ns ± 1.66 ns per loop (mean ± std. dev. of 7 runs, 1,000,000 loops each) 

Note: most of the compiled regular expressions in platform.py can be moved into the methods using them, as most results are cached. This would reduce the importtime for platform even further:

Main: The speed of "import platform" is: 8.231517 +- 0.499458 [ms] Regular expressions adapted: The speed of "import platform" is: 7.182120 +- 0.726896 [ms] 

• Issue: Remove legacy ironpython 2 version check #102491

[hauntsaninja]

Thanks, this looks good. Would you mind adding the news entry?

[hauntsaninja]

Hm, not an issue with this PR, but I was curious what IronPython is doing. It looks like their platform.py has https://github.com/IronLanguages/ironpython3/blob/f41afc44534786721b89e1efb8e50c4232ee1224/Src/StdLib/Lib/platform.py#L1141 and https://github.com/IronLanguages/ironpython3/blob/f41afc44534786721b89e1efb8e50c4232ee1224/Src/StdLib/Lib/platform.py#L1187

Weirdly, IronPython's docs indicates that its sys.version would not match the regex we have or the regex they have in their platform.py.

[eendebakpt]

Hm, not an issue with this PR, but I was curious what IronPython is doing. It looks like their platform.py has https://github.com/IronLanguages/ironpython3/blob/f41afc44534786721b89e1efb8e50c4232ee1224/Src/StdLib/Lib/platform.py#L1141 and https://github.com/IronLanguages/ironpython3/blob/f41afc44534786721b89e1efb8e50c4232ee1224/Src/StdLib/Lib/platform.py#L1187

Weirdly, IronPython's docs indicates that its sys.version would not match the regex we have or the regex they have in their platform.py.

@hauntsaninja Good point. I created an issue IronLanguages/ironpython3#1667. Based on the decision there, can you (as core dev) make a decision on the other ironpython regular expression.

[hauntsaninja]

Thank you!