Enable Intel AVX512_FP16 instructions and test

[Cui, Lili]

> >>> As to the message (I'm sorry for adjusting my prior suggestion), how
> >>> about "destination must be distinct from source registers"?
> >>>
> >> I am confused here, do I need to make some changes ?
> >
> > Well - use the new suggested text?
> 
> And just to clarify - ideally with these two remaining small items addressed,
> I'm okay with the patch now; afaic no need for another re-posting before you
> commit the result. I may subsequently try to deal with the two items you
> indicated you wouldn't want to address.
> 
Thank you Jan, I know one item that you want to change is "DistinctDest", you don't like to add this new insn attribute, maybe you have a better way to deal with it. what's the other one?

Lili.

> Jan