Currently if TestPoll fails because an unexpected event fired, we just
print that it happened, not which one fired. #49380 has been difficult
to reproduce, so printing more information for this case would be
helpful.
Updates #49380.
Change-Id: I820c4b634536565487ee1474f8afe092a8a4443b
Reviewed-on: https://go-review.googlesource.com/c/sys/+/363714
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
