bpo-44009: Provide "python3.x-intel64" for Apple Silicon Macs (GH-25810)

bpo-44009: Provide "python3.x-intel64" for Apple Silicon Macs (GH-25810)

This allows reliably forcing macOS universal2 framework builds
to run under Rosetta 2 Intel-64 emulation on Apple Silicon Macs
if needed for testing or when universal2 wheels are not yet
available.
(cherry picked from commit 0cb33da1cc9cebb9b2d67d446feb1cfd36fe7f55)

Co-authored-by: Ned Deily <nad@python.org>
Automerge-Triggered-By: GH:ned-deily
Co-authored-by: Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com>