x86/Intel: correct AVX512F scatter insn element sizes

I clearly screwed up in 6ff00b5e ("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).

(cherry picked from commit 987e8a90)