test: new testcase for gccgo bug

Updates #33020

Change-Id: I82554ef20ea35e0087fd9ecd9548c2dfeacdc617
Reviewed-on: https://go-review.googlesource.com/c/go/+/186697
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

test/fixedbugs/issue33020.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
+
+var G1 int
+var G2 int
+var G3 int
+var G4 int
+var G5 int
+var G6 int
+var G7 int
+var G8 int
+var G9 int
+var G10 int

test/fixedbugs/issue33020.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"
+
+var N n
+
+type n struct{}
+
+func (r n) M1() int  { return a.G1 }
+func (r n) M2() int  { return a.G2 }
+func (r n) M3() int  { return a.G3 }
+func (r n) M4() int  { return a.G4 }
+func (r n) M5() int  { return a.G5 }
+func (r n) M6() int  { return a.G6 }
+func (r n) M7() int  { return a.G7 }
+func (r n) M8() int  { return a.G8 }
+func (r n) M9() int  { return a.G9 }
+func (r n) M10() int { return a.G10 }

test/fixedbugs/issue33020.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 33020: gccgo undefined behavior with inlinable function
+
+package ignored