Merge "libprocessgroup: Activate controllers in cgroup v2 hierarchy at...

Merge "libprocessgroup: Activate controllers in cgroup v2 hierarchy at intermediate levels" am: 9accb43a am: 6d02614a

Original change: https://android-review.googlesource.com/c/platform/system/core/+/1783849

Change-Id: If62c924b9c93e3a4b1d3181b4659a696d4e073d5