“SNL” has a tendency to book recently anointed Oscar winners and nominees as hosts. Last year, it was J.K. Simmons a few weeks before the ceremony, and Michael Keaton a couple months after. This season, it is Brie Larson’s turn, with the holiday serving as a tie-in to her award-winning role. It is a sound strategy, as that Academy recognition generally guarantees that these people can act. They do not necessarily have to be funny, so long as they fulfill their roles just as the writing asks them to. Brie proves herself perfectly capable, and the writing lives up to her level.