[CI] pypy jobs in Github Actions keep being mysteriously cancelled

[abravalheri]

The pypy jobs are randomly being cancelled by the GHA and/or host machine without no obvious reason (and no apparent test failure). For example: https://github.com/pypa/setuptools/actions/runs/11617212198/job/32351913143#step:9:51

This is very inconvenient because it creates false negatives and blocks the rest of the pipeline (e.g. prevents releases).

Does anyone have any idea of what can be causing it?