Merge "libprocessgroup: Fix warnings when legacy schedtune cgroup is absent"...

Merge "libprocessgroup: Fix warnings when legacy schedtune cgroup is absent" am: 3b0ec907 am: 60750f31 am: 67d6fba4 am: f7389833

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1685992

Change-Id: Icf3f264c6e32767c5cfcbc35c3de81d1b7335870