John Hopewell Chief International CorrespondentPenelope Cruz and Antonio Banderas are Spain’s biggest Hollywood names, and Pedro Almodovar’s most frequent stars, but – extraordinary as it may seem – to date, they’ve had just two minutes on screen together, in the opening scene of 2013’s “I’m So Excited.”In comedy “Official Competition,” a frontrunner for Venice selection next Monday, they get to share the screen for the whole of the film.