Twig 2 supports hassers for the attribute operator

[stof]

Twig 1 only supports getters and issers for the attribute operator (.), but Twig 2 added support for hassers.
Currently the bundle marks this as an undefined property (and generates the access with hasFoo on autocomplete). It would be great if it could change its behavior based on the Twig version instead.

[Haehnchen]

related twigphp/Twig#1969

     * if not, and if ``foo`` is an object, check that ``getBar`` is a valid method;
     * if not, and if ``foo`` is an object, check that ``isBar`` is a valid method;
     * if not, and if ``foo`` is an object, check that ``hasBar`` is a valid method;

[Haehnchen]

done. but without Twig version check, overhead for this feature