Available right now on Netflix, this 2017 techno-thriller seems to have a lot going for it: a cast that includes Tom Hanks, Emma Watson, Karen Gillan, John Boyega and Bill Paxton in his final role and a plot focussed on subject matter lifted directly from news headlines. So it’s something of a surprise that it all falls so horribly, clumsily flat. When Mae Holland (Emma Watson) manages to get a…