[RyuJIT] Enable CORINFO_INTRINSIC Round, Ceiling, and Floor to generate ROUNDSS and ROUNDSD

[tannergooding]

SSE4.1 added the ROUNDSS and ROUNDSD instructions. For machines which support them, we should support emitting them for the Round, Ceiling, and Floor methods in System.Math and System.MathF.

[tannergooding]

FYI. @fiigii

I think this will be more readily possible once dotnet/coreclr#14020 goes in (since we will be able to properly distinguish SSE4.1 from SSE3; today they are combined into the InstructionSet_SSE3_4 value)

[fiigii]

I think this will be more readily possible once dotnet/coreclr#14020 goes in (since we will be able to properly distinguish SSE4.1 from SSE3; today they are combined into the InstructionSet_SSE3_4 value)

Yes, I think so, and it will be finished soon. Are you implementing these math intrinsics?

[tannergooding]

I plan on doing so, if someone else doesn't get to them first.