test: disable large type/stack frame tests for gccgo

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/40370052

test/fixedbugs/bug385_32.go

@@ -9,7 +9,7 @@
 
 package main
 func main() {
-	var arr [1000200030]int   // ERROR "type .* too large"
+	var arr [1000200030]int   // GC_ERROR "type .* too large"
 	arr_bkup := arr
 	_ = arr_bkup
 }

test/fixedbugs/bug385_64.go

@@ -12,7 +12,7 @@ package main
 
 var z [10<<20]byte
 
-func main() { // ERROR "stack frame too large"
+func main() { // GC_ERROR "stack frame too large"
 	// seq 1 206 | sed 's/.*/	var x& [10<<20]byte; z = x&/'
 	var x1 [10<<20]byte; z = x1
 	var x2 [10<<20]byte; z = x2