test: add fixed GoSmith bugs reported on the gcc Bugzilla

Change-Id: I36b57f3e299a4f96b8b5aa55c9c224d888229684
Reviewed-on: https://go-review.googlesource.com/1790
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

test/fixedbugs/gcc61264.go

diff --git a/test/fixedbugs/gcc61264.go b/test/fixedbugs/gcc61264.go
new file mode 100644
index 0000000..d4e05f4
--- /dev/null
+++ b/test/fixedbugs/gcc61264.go
@@ -0,0 +1,13 @@
+// compile
+
+// Copyright 2014 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.
+
+// PR61264: IncDec statements involving composite literals caused in ICE in gccgo.
+
+package main
+
+func main() {
+        map[int]int{}[0]++
+}