test: explanatory comments [c-g]*

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/5656103
diff --git a/test/func2.go b/test/func2.go
index 87e7819..b5966a9 100644
--- a/test/func2.go
+++ b/test/func2.go
@@ -1,9 +1,12 @@
-// $G $F.go || echo BUG: should compile
+// compile
 
 // Copyright 2009 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.
 
+// Test function signatures.
+// Compiled but not run.
+
 package main
 
 type t1 int