Updates golang/go#30971
Updates golang/go#31040

Change-Id: I305fbddb6f79cbe3d7e29225841309ab00b1e7dd
Reviewed-on: https://go-review.googlesource.com/c/go/+/169239
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>