Fixes #22739

Change-Id: I374c29d237c498c9e5ac848b01f6d49d7c41b31f
Reviewed-on: https://go-review.googlesource.com/77930
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>