Fixes #22696

Change-Id: Ibe4628f71d64a2b36b655ea69710a925924b12a3
Reviewed-on: https://go-review.googlesource.com/122586
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Austin Clements <austin@google.com>