[dev.typeparams] cmd: update vendored golang.org/x/tools to 337cebd2c151

Update vendored golang.org/x/tools repo to pick up CL 339250 for
assembly function check for register ABI.

This is done with

	cd GOROOT/cmd
	go get golang.org/x/tools@master
	go mod tidy
	go mod vendor

Update cmd/vet tests as the error ouput changes in CL 301949.
The error message now includes full package-qualified name.

Change-Id: I52dc7223aee9e011214254488bacf02dc5b4c2ef
Reviewed-on: https://go-review.googlesource.com/c/go/+/341149


Trust: Cherry Mui <cherryyz@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>