LAS VEGAS — The magic trick, the big rabbit out of the hat, is how he remains calm amid the calamity. Tranquil Bob, he’s called. Even Steven. And it’s not just on the ice, where Florida Panthers goalie Sergei Bobrovsky returns for Game 1 of the Stanley Cup Final on Saturday night. “It’s everywhere,’’ he says. Everywhere? “Everywhere in my life, I want to be calm,’’ he says. Does he get angry driving in traffic? “No, never,’’ he says. Stressed being late for an appointment? “No, not at all,’’ he says.