runsc: Only uninstall cgroup for sandbox stop.
runsc: Only uninstall cgroup for sandbox stop.

PiperOrigin-RevId: 231263114
Change-Id: I57467a34fe94e395fdd3685462c4fe9776d040a3

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor