Handle IROps introduced by the arm64 port:
Iop_ZeroHI64ofV128, Iop_ZeroHI96ofV128, Iop_ZeroHI112ofV128,
Iop_ZeroHI120ofV128, Iop_Abs64Fx2, Iop_Neg64Fx2



git-svn-id: svn://svn.valgrind.org/valgrind/trunk@13860 a5019735-40e9-0310-863c-91ae7b9d1cf9