This fixes 'go test ./...' in the root of the tools repo with GO111MODULE=on.
Updates golang/go#27858
Change-Id: I7492d2a2406997a399fe2badd24882fcb19d37c5
Reviewed-on: https://go-review.googlesource.com/c/139320
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>