cmd/trace: track each G's state explicitly
Currently the trace tool tracks an overall counts of goroutine states,
but not the states of any individual goroutine. We're about to add
more sophisticated blocked-state tracking, so add this tracking and
base the state counts off the tracked goroutine states.
Change-Id: I943ed61782436cf9540f4ee26c5561715c5b4a1d
Reviewed-on: https://go-review.googlesource.com/30703
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>