JIT CI will break with deprecation of x86_64 macOS runners

[JacobCoffee]

GitHub is starting random brownouts for macOS runners running under x86_64 arch and it will eventually be deprecated fully.

The https://github.com/python/cpython/blob/main/.github/workflows/jit.yml file will need to be updated to run under rosetta. This, or find alternatives (cirrus-ci, buildbots?)

Linked PRs

• gh-137638: Use macos-15-intel in GitHub Actions #139154

[hugovk]

See also https://discuss.python.org/t/dropping-intel-mac-to-tier-2/102100 and #137638.

[JacobCoffee]

github: 'just kidding: https://github.blog/changelog/2025-09-19-github-actions-macos-13-runner-image-is-closing-down/#notice-of-macos-x86_64-intel-architecture-deprecation'

[hugovk]

Let's close as a duplicate of #137638 and update to use macos-15-intel instead.