This covers GitLab.com shared runner configuration changes and
optimizations made to reduce load on the Gitaly file servers for the
`gitlab-org/gitlab` project on GitLab.com.

* https://gitlab.com/gitlab-org/gitlab/issues/39134
* https://gitlab.com/gitlab-org/gitlab/merge_requests/21646

Closes https://gitlab.com/gitlab-org/gitlab/issues/118468