Also includes a trivial test of I/O latency. (Mostly useful to be invoked
from checkin to poll disk-free and latency issues. Also moderately useful
to see in a bugreport.)
Also make "dumpsys netstat" a non-no-op, in case we want this data.
Change-Id: Ia93550a23ca6b35586c5d9217890ee0a5801aae1
