test: fix copyright year in new test case

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5631044

test/fixedbugs/bug405.go

 // $G $D/$F.go && $L $F.$A && ./$A.out
 
-// Copyright 2009 The Go Authors. All rights reserved.
+// Copyright 2012 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.