Issue 30067: _osx_support.py: misplaced flags in re.sub()

Lib/_osx_support.py contains the following line:

    flags = re.sub(r'-arch\s+\w+\s', ' ', flags, re.ASCII)

But the 4th re.sub() argument is the maximum number of substitutions, so this is equivalent to:

    flags = re.sub(r'-arch\s+\w+\s', ' ', flags, count=256)

It was probably meant to be:

    flags = re.sub(r'-arch\s+\w+\s', ' ', flags, flags=re.ASCII)


This bug was found using pydiatra:
http://jwilk.net/software/pydiatra