Handle and instrument an extra rounding-mode argument as added by
vex r2809 to the following primops:

  Iop_Add32Fx4, Iop_Sub32Fx4, Iop_Mul32Fx4, Iop_Div32Fx4, 
  Iop_Add64Fx2, Iop_Sub64Fx2, Iop_Mul64Fx2, Iop_Div64Fx2, 
  Iop_Add64Fx4, Iop_Sub64Fx4, Iop_Mul64Fx4, Iop_Div64Fx4,
  Iop_Add32Fx8, Iop_Sub32Fx8, Iop_Mul32Fx8, Iop_Div32Fx8,



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13781 a5019735-40e9-0310-863c-91ae7b9d1cf9