Clean up `info/refs_XXXXXX` as part of housekeeping
It can happen that we leave behind stale refs_XXXXXX
files, which aren't ever cleaned up and createby Git. Depending on the number of references those may be hundreds of megabytes in size. We should clean up stale refs files as part of our housekeeping tasks.
See e.g. https://gitlab.com/gitlab-org/gitlab/-/issues/351415#note_830077042, where we have accumulated 35GB of those files.