Revert "libprocessgroup: uid/pid hierarchy for cgroup v2"

Revert "sepolicy: rules for uid/pid cgroups v2 hierarchy"

Revert submission 1511692-cgroup v2 uid/pid hierarchy

Reason for revert: Causing intermittent cgroup kernel panics
Reverted Changes:
I80c2a069b:sepolicy: rules for uid/pid cgroups v2 hierarchy
I73f3e767d:libprocessgroup: uid/pid hierarchy for cgroup v2

Bug: 174776875
Change-Id: I2af586d63bb0312407b90b52909330cde4b7b074
Test: Locally reverted and booted 100 times without kernel panic