cmd/go: set GoVersion for files on the command line with vet
For: #65612 Fixes: #66092
For now, we will align the behavior such that vet and the compiler agree
that gover.Local() will be used for command-line-files.
We expect to change this to set the goversion as the containing module's go
version.
Change-Id: If7f2ea3a82e8e876716f18dacc021026de175a93
Reviewed-on: https://go-review.googlesource.com/c/go/+/593156 Reviewed-by: Michael Matloob <matloob@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Sam Thanawalla <samthanawalla@google.com>