Fixes #19416

Change-Id: I23c69ff637abaa202909f1cba6ed41b3cfe3d117
Reviewed-on: https://go-review.googlesource.com/37812Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>