Directed by Alejandro González Iñárritu Written by Alejandro González Iñárritu, Nicolás Giacobone, Alexander Dinelaris, & Armando Bo  Starring Michael Keaton, Edward Norton, Emma Stone, Naomi Watts, Zach Galifianakis, Andrea Riseborough, & Amy Ryan NOW PLAYING in NYC & Select Theaters A has-been actor tries to reestablish relevance: It doesn’t sound like the freshest of premises. ‘Sunset Boulevard’s’ Norma Desmond prepped…