x86/Intel: correct AVX512F scatter insn element sizes

I clearly screwed up in 6ff00b5e12e7 ("x86/Intel: correct permitted
operand sizes for AVX512 scatter/gather") giving all AVX512F scatter
insns Dword element size. Update testcases (also their gather parts),
utilizing that there previously were two identical lines each (for no
apparent reason).
4 files changed