IronPython parsing of sys.version

[eendebakpt]

Description

In https://github.com/python/cpython/pull/102492 the IronPyhon 2.x version parsing is removed. We are wondering whether the other regular expression parsing a version tag, e.g. https://github.com/python/cpython/pull/102492/files#diff-cb1ba6039236dca71c97ea898f2798c60262c30614192862259889f839e4d503L1043-L1048 is still correct and relevant for ironpython as there is a difference with the one in current ironpython git: https://github.com/IronLanguages/ironpython3/blob/f41afc44534786721b89e1efb8e50c4232ee1224/Src/StdLib/Lib/platform.py#L1141

@slozier