Everything old is new again. This is the season when brains are turned off, rebuilding for the fall, when they will be once again overused. Luckily Hollywood has your back. Starting with the sequel “Avengers: Age of Ultron,” out Friday, many of this summer’s blockbusters boast numbers or new secondary titles, and even the original films tend to be mish-mashes of proven entities. But hey, at least there’s zero Adam Sandler films!