test: new testcase for gccgo compiler failure

Updates #33219

Change-Id: I1702d4c630bb891fcb8b59e775dd3f1673cd8640
Reviewed-on: https://go-review.googlesource.com/c/go/+/187057
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

test/fixedbugs/issue33219.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 interface {
+	M(i interface{}) interface{}
+}
+
+var a1 A
+var a2 A
+
+func V(p A, k, v interface{}) A {
+	defer func() { a1, a2 = a2, a1 }()
+	return a1
+}

test/fixedbugs/issue33219.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 Service uint64
+
+var q *Service
+var r *Service
+
+type f struct{}
+
+var fk f
+
+func No(s a.A, qq uint8) *Service {
+	defer func() { q, r = r, q }()
+	return q
+}
+
+func Yes(s a.A, p *uint64) a.A {
+	return a.V(s, fk, p)
+}

test/fixedbugs/issue33219.dir/c.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 c
+
+import (
+	"a"
+	"b"
+)
+
+type BI interface {
+	Another(pxp a.A) int32
+}
+
+//go:noinline
+func BRS(sd a.A, xyz int) *b.Service {
+	x := b.Yes(sd, nil)
+	return b.No(x, 1)
+}

test/fixedbugs/issue33219.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 33219: gccgo assert in "implements_interface()"
+
+package ignored