limiter: Ignore `total_inactive_file` instead of `inactive_file`

In !6508 (merged), we implemented a fix to ignore highly evictable Page Caches from cgroup memory threshold. The used metric was parent cgroup's inactive_file. Unfortunately, that metric reflects the inactive Page Caches of direct processes inside the parent cgroup. It doesn't account for the indirect processes in children repository cgroups. We don't spawn any process in the parent cgroup. So, the fix was useless.

In Cgroup V1, memory.stat has total_inactive_file. It's exactly what we are looking for. In Cgroup V2, inactive_file includes all of its substree consumptions. So, we can keep using that field.