[release-branch.go1.12] cmd/go/internal/get: fix strayed verbose output on stdout

Fixes #31783

Change-Id: I3cc0ebc4be34d7c2d2d4fd655bfd0c2515ff3021
Reviewed-on: https://go-review.googlesource.com/c/go/+/174739


Reviewed-by: Jay Conrod <jayconrod@google.com>
Run-TryBot: Jay Conrod <jayconrod@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
(cherry picked from commit fad365ba)
Reviewed-on: https://go-review.googlesource.com/c/go/+/175419


Run-TryBot: Andrew Bonventre <andybons@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>