Fixes #16197

Change-Id: Icaabacbb22bc18c52b9e04b47385ac5325fcccd1
Reviewed-on: https://go-review.googlesource.com/24505
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>