Just try to sit still during Maurice Ravel’s homages to two of the world’s greatest waltz composers, Franz Schubert and Johann Strauss.   John Adams’ 1995 showpiece was inspired by two important Russians, Igor Stravinsky and the celebrated author of several witty and erudite books on music, Nicolas Slonimsky. Joyce Yang returns to Abravanel Hall to perform a work written by, and for, the Paganini of the piano, which took him over 25 years to write. Ravel hoped La Valse would become a “choreographed poem,” but Diaghilev told him he hadn’t written a ballet but rather a painting of one.   Maestro Thierry Fischer conducts.