Update #31269

Change-Id: I0e7184420055b8dfd23688dab9f9d8cba1fa2485
Reviewed-on: https://go-review.googlesource.com/c/go/+/170892
Run-TryBot: Keith Randall <khr@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>