It’s a little surprising that “X” marks director Ti West’s first film for A24 since his approach to horror — emphasizing character and mood over jump scares, building slowly and steadily to a big bloody blowout — is so synced up with their house style. “X” is also his first feature since 2016, and his first horror film since 2013’s “The Sacrament”; he’s kept busy in the years since with plenty of television work, but this is what he does best, and it’s about time he got back to it.