dumpstate: report process times

(cherry picked from commit 0751efa6)

- Fix per-pid helper to pick up comm if cmdline is empty
  and assume kernel thread.
- Add per pid report command line user time if not kernel thread,
  system time and I/O time, plus percentage if non zero.

Bug: 26966375
Change-Id: I6b499f535cc3687eb468b32ae39e7d151dffb11f