If Alfred Hitchcock had been alive to make 1980s cryptoporn, he would have made “Body Double” (1984). Let me explain. In some dark, horny corners, it’s cult classic. It launched the career of Melanie Griffith. It’s a kinky update of “Rear Window” where a claustrophobic actor replaces a bed-ridden photographer, a hard-core vixen replaces a Madison Avenue princess and Hollywood hills replace Manhattan walk-ups. Hitchcock devotee Brian De Palma wrote and directed. Frankie Goes to Hollywood makes a cameo in a music video that launched a thousand rubouts. I like to watch… uh, I mean, I liked to watch it.