Sam Rockwell plays a time traveler from an apocalypse come to save humanity from its own reliance on machines in a madcap sci-fi comedy. There was a time in the not-too-distant past when a movie as intensely anti-phone as “Good Luck, Have Fun, Don’t Die” would probably have been seen as insufferably preachy, or, at the very least, deeply embarrassing. Think of the period in the mid-2010s when people had generally positive opinions about Elon Musk, when Jason Reitman’s internet morality play “