x86: add missing pseudo ops for VPCLMULQDQ ISA extension

x86: add missing pseudo ops for VPCLMULQDQ ISA extension

While the ISA extensions doc suggests them to be made available just
like the SDM does for the PCLMULQDQ ISA extension, these weren't added
when supposrt for the new extension was introduced.

Also make sure the 64-bit non-AVX512 test actually tests VEX encodings,
not EVEX ones.