Fixes breakage accidentally introduced by https://golang.org/cl/291711.

Fixes #44295

Change-Id: I76f3e5577d1d24027d4ed2a725b5b749ab2d059c
Reviewed-on: https://go-review.googlesource.com/c/go/+/292629


Trust: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>