This weekend, when “Saturday Night Live” kicks off its 50th season, the momentous event will surely stir up nostalgic memories for generations of fans. Since 1975, Lorne Michaels’ weekly show has given us Bill Murray, Chevy Chase, Gilda Radner, Adam Sandler, Eddie Murphy, Tina Fey, Will Ferrell, Kristen Wiig, Amy Poehler, Maya Rudolph, Conan O’Brien,...