+ test, release note

Fixes #28308

Change-Id: I190e2fe513eeb6b90b0398841f67bf52510b5f59
Reviewed-on: https://go-review.googlesource.com/c/go/+/667596


Auto-Submit: Alan Donovan <adonovan@google.com>
Commit-Queue: Alan Donovan <adonovan@google.com>
Reviewed-by: Jonathan Amsterdam <jba@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>