cmd: vendor x/tools@9fccddc

cmd: vendor x/tools@9fccddc

(This brings in CL 703995.)

For #71859

Change-Id: I823f2da9ebbdbef943cb37123d44a7ad2e6d708b
Reviewed-on: https://go-review.googlesource.com/c/go/+/703896
Reviewed-by: Michael Matloob <matloob@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Alan Donovan <adonovan@google.com>
Reviewed-by: Michael Matloob <matloob@google.com>