Run the docker cleanup on a GitHub runner (#2710)
Summary:
`clean-nightly-docker.yml` moves from `linux.2xlarge` to `ubuntu-24.04`.
Despite the name the job never touches Docker — it only calls `actions/delete-package-versions` against the GitHub packages API, so it has no reason to hold a self-hosted box.
`build-nightly-docker.yml` is **not** included. It builds the image, then `docker run`s it to read `torch.__version__` out of the result before tagging and pushing. On OSDC the build happens on an out-of-cluster BuildKit pool and the image never lands on the runner, and there is no local daemon to run it with. Moving it means deriving the version without executing the image, which is a change to what the job does rather than to where it runs.
Authored with Claude Code.
Pull Request resolved: https://github.com/pytorch/benchmark/pull/2710
Reviewed By: georgehong
Differential Revision: D122498677
Pulled By: huydhn
fbshipit-source-id: e863455e006d9d036cb5a112f21b6ddd205fa23b