ci: run ffi-check on aarch64 linux

[davidhewitt]

Still investigating segmentation fault in the pydantic-core test suite...

[davidhewitt]

Thanks for moving this forward @messense! Looks like it took ~10 minutes on that step, so we probably want to move it to its own job.

It also ran on Python 3.10 (I guess that's what ships with ubuntu 22.04), I guess we want to run on 3.12 or 3.13 really. Maybe we can use uv to download a newer Python inside the image.

I guess I am now also wondering, should we be trying more than just ffi-check for these architectures? e.g. we could try to run more / all of the test suite. As PyO3 / Rust usage is getting wider across the Python ecosystem, good coverage of less popular architectures probably is more important now than it was a couple of years ago.

... so time to load up CI even more? 😢

[messense]

Alternative we can consider run Linux aarch64 pipeline natively on Cirrus CI before GH Actions aarch64 Linux runner becoming available for public repos?