Fixes #22981

Change-Id: I449eb7b5e022401e80a3ab138063e2f4499fbdf8
Reviewed-on: https://go-review.googlesource.com/81855Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>