Fix unconsistent behavior with "get" and "is"

lib/Twig/Template.php

@@ -604,6 +604,9 @@ abstract class Twig_Template implements Twig_TemplateInterface
             } else {
                 $methods = get_class_methods($object);
             }
+            // sort values to have consistent behavior, so that "get" methods win precedence over "is" methods
+            sort($methods);
+
             $cache = array();
 
             foreach ($methods as $method) {