When is an actor’s feature-length debut not really an actor’s feature-length debut? If you’re George Clooney, it’s when it takes 37 years to release, by which time you’re almost 60 and a superstar. Like so many others, a young Clooney entered Hollywood under the most inauspicious circumstances: by nabbing a couple of early roles in bargain-basement horror flicks. His first picture to land in cinemas was the 1984 horror comedy Return to Horror Hi…