[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/+/174739Reviewed-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>

src/cmd/go/internal/get/vcs.go

@@ -424,8 +424,8 @@ func (v *vcsCmd) run1(dir string, cmdline string, keyval []string, verbose bool)
 	cmd.Dir = dir
 	cmd.Env = base.EnvForDir(cmd.Dir, os.Environ())
 	if cfg.BuildX {
-		fmt.Printf("cd %s\n", dir)
-		fmt.Printf("%s %s\n", v.cmd, strings.Join(args, " "))
+		fmt.Fprintf(os.Stderr, "cd %s\n", dir)
+		fmt.Fprintf(os.Stderr, "%s %s\n", v.cmd, strings.Join(args, " "))
 	}
 	out, err := cmd.Output()
 	if err != nil {