We see that in gitlab-org/gitlab-ee#3664 that if we log a lot of
data in Sidekiq workers, the number of open file descriptors
reaches over 1000. To avoid this, we can memoize the logger per
thread via RequestStore.
Closesgitlab-org/gitlab-ee#3664
If this method was called for a file that didn't exist, we attempted to
first `build` it. But if the file wasn't writeable, such as a symlink
pointing to an unmounted filesystem, the method would just hang and
eventually timeout.
Further, this was entirely pointless since we were creating a file and
then shelling out to `tail`, eventually returning an empty Array. Now we
just skip building it and return the empty Array straight away.
