runtime: move printing of extra newline

No functional changes, makes vet happy.

Updates #11041

Change-Id: I59f3aba46d19b86d605508978652d76a1fe7ac7b
Reviewed-on: https://go-review.googlesource.com/27125
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/runtime/testdata/testprogcgo/threadprof.go

@@ -84,8 +84,8 @@ func CgoExternalThreadSignal() {
 
 	out, err := exec.Command(os.Args[0], "CgoExternalThreadSignal", "crash").CombinedOutput()
 	if err == nil {
-		fmt.Println("C signal did not crash as expected\n")
-		fmt.Printf("%s\n", out)
+		fmt.Println("C signal did not crash as expected")
+		fmt.Printf("\n%s\n", out)
 		os.Exit(1)
 	}