test: match gccgo error messages for bug081.go.

bug081.go:9:9: error: expected type

R=rsc
CC=golang-dev
https://golang.org/cl/4280071

test/fixedbugs/bug081.go

@@ -6,7 +6,7 @@
 
 package main
 
-const x x = 2 // ERROR "loop"
+const x x = 2 // ERROR "loop|type"
 
 /*
 bug081.go:3: first constant must evaluate an expression