BuilderHelpers::normalizeValue could normalize enum values

[Ondřej Mirtes]

Enum values are objects. So in normalizeValue they end up in throw new \LogicException('Invalid value').

Something like this code could be added at the end of the method to handle enum values as well:

        if (is_object($defaultValue)) {
            $className = get_class($defaultValue);
            $isEnum = function_exists('enum_exists') && enum_exists($className, false);
            if ($isEnum) {
                return new Node\Expr\ClassConstFetch(
                    new FullyQualified($className),
                    new Node\Identifier($defaultValue->name)
                ));
            }
        }

Maybe there are other cases that need handling, but I'm not sure if we can go from "object value" to "Expr" safely for them too.