Fixes #21436

Change-Id: I56f43e2852696c28edbcc772a54125a9a9c32497
Reviewed-on: https://go-review.googlesource.com/55262Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>