Fix VM memory allocation optimizations by reducing what we allocate on the heap

internal/builtins/open.go

@@ -66,10 +66,10 @@ func Open(args ...object.Object) object.Object {
 		perm     uint32 = 0640
 	)
 
-	filename = args[0].(*object.String).Value
+	filename = args[0].(object.String).Value
 
 	if len(args) == 2 {
-		mode = args[1].(*object.String).Value
+		mode = args[1].(object.String).Value
 	}
 
 	flag, err := parseMode(mode)
@@ -82,5 +82,5 @@ func Open(args ...object.Object) object.Object {
 		return newError("IOError: %s", err)
 	}
 
-	return &object.Integer{Value: int64(fd)}
+	return object.Integer{Value: int64(fd)}
 }