[AVX512] Remove alternate data type versions of VALIGND, VALIGNQ, VMOVSHDUP...

[AVX512] Remove alternate data type versions of VALIGND, VALIGNQ, VMOVSHDUP and VMOVSLDUP. They don't have any tests and I don't think they can be selected. If they are truly needed they should be implemented with patterns against the normal instructions and not separate instructions.

llvm-svn: 256475