(TestStackBarrierProfiling is failing on darwin/arm.)

Change-Id: I8006d6222ccafc213821e02105896440079caa37
Reviewed-on: https://go-review.googlesource.com/17091Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>