ptrace: drop old FIXME
ptrace: drop old FIXME

The globalPool uses a sync.Once mechanism for initialization,
and no cleanup is strictly required. It's not really feasible
to have the platform implement a full creation -> destruction
cycle (due to the way filters are assumed to be installed), so
drop the FIXME.

PiperOrigin-RevId: 236385278
Change-Id: I98ac660ed58cc688d8a07147d16074a3e8181314

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