Previously, on Unix systems, when the profiler was enabled or disabled,
we called setitimer once per thread. With this change we instead call
it once per process.
Change-Id: I90f0189b562e11232816390dc7d55ed154bd836d
Reviewed-on: https://go-review.googlesource.com/c/go/+/240003
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Keith Randall <khr@golang.org>