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

internal/builtins/builtins.go

@@ -72,6 +72,6 @@ func init() {
 	}
 }
 
-func newError(format string, a ...interface{}) *object.Error {
-	return &object.Error{Message: fmt.Sprintf(format, a...)}
+func newError(format string, a ...interface{}) object.Error {
+	return object.Error{Message: fmt.Sprintf(format, a...)}
 }