[HLSL] implement `WaveGetLaneIndex` intrinsic

[llvm-beanz]

Implement HLSL WaveGetLaneIndex intrinsic:

https://learn.microsoft.com/en-us/windows/win32/direct3dhlsl/WaveGetLaneIndex

AC:

• The intrinsic is implemented and lowered to LLVM-IR
• Tests are implemented to validate that the IR is generated correctly

[damyanp]

Marking re-estimate this. Since this was originally refined, we have a different approach to implementing intrinsics and the way we've been estimating intrinsics has changed quite a bit.