Merge "Revert "Migrate the blkio controller to the v2 cgroup hierarchy"" am: ddfa08b98b am: 2929e71d77

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2378329

Change-Id: I564d3c7a6f260aa5f84ab0fa155df15dd5963fd3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>