all: update golang.org/x/* dependencies

Updates src/ and src/cmd/* dependencies, using

    go mod vendor

as well as

    updatestd -branch=master -goroot=$GOROOT

This change was ran in anticipation of bringing in x/net/http2 CL 237957.

For #32112.
For #36905.

Change-Id: If8cefc348463b6d82d85020b57db411213720ef8
Reviewed-on: https://go-review.googlesource.com/c/go/+/296789


Trust: Emmanuel Odeke <emmanuel@orijtech.com>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Emmanuel Odeke <emmanuel@orijtech.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>