test: new testcase for gccgo compiler problem

Test case with code that caused a gccgo error while emitting export
data for an inlinable function.

Updates #34577.

Change-Id: I28b598c4c893c77f4a76bb4f2d27e5b42f702992
Reviewed-on: https://go-review.googlesource.com/c/go/+/198057
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

test/fixedbugs/issue34577.dir/a.go

+// Copyright 2019 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 a
+
+type A struct {
+	x int
+}
+
+//go:noinline
+func W(a A, k, v interface{}) A {
+	return A{3}
+}

test/fixedbugs/issue34577.dir/b.go

+// Copyright 2019 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 b
+
+import "a"
+
+type B struct {
+	s string
+}
+
+func (b B) Func(x a.A) a.A {
+	return a.W(x, k, b)
+}
+
+type ktype int
+
+const k ktype = 0

test/fixedbugs/issue34577.go

+// compiledir
+
+// Copyright 2019 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.
+
+// Issue 34577: gccgo compiler error emitting export data
+
+package ignored