reflect: fix test of whether structs are identical

The old code worked with gc, I assume because the linker
unified identical strings, but it failed with gccgo.

R=rsc
CC=gobot, golang-dev
https://golang.org/cl/6826063
diff --git a/test/fixedbugs/bug468.go b/test/fixedbugs/bug468.go
new file mode 100644
index 0000000..12e4997
--- /dev/null
+++ b/test/fixedbugs/bug468.go
@@ -0,0 +1,10 @@
+// rundir
+
+// 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 reflect package was not correctly checking field names
+// when checking for struct assignability.
+
+package ignored