Python 3.14 installer is for macOS 10.15 and later

[hugovk]

For python/cpython#137749.

The Python 3.14 installer is for macOS 11 and later.

---

I also added tests, which found an existing bug (tests find bugs? 🤯).

The previous f"for macOS {'10.13' if v >= (3, 12, 6) else '10.9'} and later" was giving us "for macOS 10.9 and later" for 3.12.10 instead of "for macOS 10.13 and later.

See: https://www.python.org/downloads/release/python-31210/

This is because we were minor_version_tuple only gives us (x, y), not (x, y, z):

>>> v = >>> v = minor_version_tuple("3.12.10")
>>> v
(3, 12)
>>> f"for macOS {'10.13' if v >= (3, 12, 6) else '10.9'} and later"
'for macOS 10.9 and later'("3.12.10")
>>> v
(3, 12)
>>> f"for macOS {'10.13' if v >= (3, 12, 6) else '10.9'} and later"
'for macOS 10.9 and later'

Instead, let's add base_version_tuple:

>>> v = base_version_tuple("3.12.10")
>>> v
(3, 12, 10)
>>> f"for macOS {'10.13' if v >= (3, 12, 6) else '10.9'} and later"
'for macOS 10.13 and later'

---

Finally, remove some redundant code for EOL Python 3.8.

[hugovk]

We'll need to manually update https://www.python.org/downloads/release/python-31210/ and check the other 3.12 and 3.14 pages too.

[ned-deily]

The basic idea LGTM, thanks. Did you go back and check the minimum supported versions? They look about right from memory :)

[hugovk]

No, I didn't check the older binaries. This PR doesn't change the claimed version support, other than adding 3.14.0->10.15.

And fixing the 3.12.6 check, but that doesn't really matter, as there won't be any more 3.12 installers. But it means it'll work when we copy and paste it for 3.14.5 or whatever :)

We can check the binaries later and update the downloads page as necessary. Will comment on the issue.