Giving what promise to be the performances of this season, Lily Rabe, as Portia the heiress, and Al Pacino, as Shylock the usurer, invest the much-parsed trial scene of this fascinating, irksome work with a passion and an anger that purge it of preconceptions. You may find yourself trembling, as one often does when something scary and baffling starts to make sense. At the same time you’re likely to have trouble figuring out exactly where your sympathies lie. For at this moment everybody hurts.