Remove dind-rootless workaround for mounting workspace

[zxiiro]

In dind-rootless container mode, volume mounts in docker is always mounted as the root user (usermapped to the "runner' (id: 1000) in the ARC runner container. Thusly this requires a workaround:

# Workaround for dind-rootless userid mapping
WORKSPACE_ORIGINAL_OWNER_ID=$(stat -c '%u' "/var/lib/jenkins/workspace")
sudo chown -R jenkins /var/lib/jenkins/workspace

....

sudo chown -R "$WORKSPACE_ORIGINAL_OWNER_ID" /var/lib/jenkins/workspace

To get around the fact that we are using a non-root user in the docker container to run the build.

The jenkins user also appears to be some legacy user that was likely used at at time when PyTorch was using Jenkins CI. Post ARC Runner migration when all the jobs are running on ARC we should look into removing the need for this workaround and updating the user where appropriate to remove this legacy configuration.

[zxiiro]

Linking pytorch/pytorch#122922 which was ultimately merged to put the workaround in place.

[ZainRizvi]

Sounds like this is done @zxiiro?

[zxiiro]

Sounds like this is done @zxiiro?

No this is a future issue to track the removal of the workaround we put in place. The workaround to chmod stuff was put in place to allow ARC to move forward but I believe it is technical debt which at some point we should find a cleaner solution for that doesn't require so much chowing. It would likely require making some big changes to pytorch build and test code though so I don't expect this issue to be done in the near term.