Fixes #28012

Change-Id: I711ebaabf63194e3d2c608d829da49c51a294d74
Reviewed-on: https://go-review.googlesource.com/c/go/+/210286
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>