[HLSL] add max/min library functions

This change exposes the max and min library functions for HLSL, excluding long, and long long doubles.
The max / min functions are supported for all scalar, vector, and matrix types.
Long and long long double support is missing in this patch because those types
don't exist in HLSL.

The full documentation of the HLSL max / min functions are available here:
https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-max
https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-min

Reviewed By: python3kgae

Differential Revision: https://reviews.llvm.org/D144309