test: add import test that caused an incorrect gccgo error

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5622048

test/fixedbugs/bug404.dir/one.go

+// 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.
+
+package one
+
+type T1 int
+type T2 []T1
+type T3 T2
+
+func F1(T2) {
+}
+
+func (p *T1) M1() T3 {
+	return nil
+}
+
+func (p T3) M2() {
+}

test/fixedbugs/bug404.dir/two.go

+// 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.
+
+// The gccgo compiler would fail on the import statement.
+// two.go:10:13: error: use of undefined type ‘one.T2’
+
+package two
+
+import "./one"
+
+var V one.T3

test/fixedbugs/bug404.go

+// $G $D/$F.dir/one.go && $G $D/$F.dir/two.go
+
+// 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.
+
+package ignored