x86: adjust {,E}VEX.W handling for PEXTR* / PINSR*

x86: adjust {,E}VEX.W handling for PEXTR* / PINSR*

PEXTR{B,W} and PINSR{B,W}, just like for AVX512BW, are WIG, no matter
that the SDM uses a nonstandard description of that fact.

PEXTRD, even with EVEX.W set, ignores that bit outside of 64-bit mode,
just like its AVX counterpart.