The Juilliard String Quartet, the granddaddy of American string quartets, played an all-Haydn program in Bailey Hall on Sunday. To hear such a vaunted group whose renown is based on their precise, graceful style perform the works of a composer who is the epitome of precise, graceful classical music is less to hear an interpretation per se than to feel definitively transported. How does one measure the standard itself, as if one sought to niggle with the canonic metric rule locked in its bank vault in Paris?