kernel - Fix process blocking forever if ^Z'd at the wrong time

* tsleep()s with timeouts were testing the wrong state field
  when determining whether a stopped thread should be woken up or not.

* Generally occured under certain circumstances when a ^Z'd process
  was then killed without first continuing it.
systat - Fix memory leak in -netbw

* Fix memory leak in -netbw.  We weren't checking for deletable
  entries once the display row hit its limit.

Reported-by: Peter Avalos