Implement the following instructions, in both ARM and Thumb
encodings:
  SSAX SXTAB16 SHASX SHSAX SHSUB16 SHSUB8
  UASX USAX UQADD16 UQASX UQSAX UHASX UHSAX REVSH

Fixes
  321363 321364 321466 321467 321468 321619 321704
  321620 321621 321692 321694 321696 321697 321703

(Vasily, w.golubev@mail.ru)



git-svn-id: svn://svn.valgrind.org/vex/trunk@2731 8f6e269a-dfd6-0310-a8e1-e2731360e62c