[clang] [llvm] [HLSL][SPIRV][DXIL] Implement `WaveActiveSum` intrinsic (PR #118580)

[Steven Perron via llvm-commits]

================

----------------
s-perron wrote:

The non-uniform group operand require the `GroupNonUniformArithmetic` capability. You should be checking for that in the test. If it is not being added, you might need to update SPIRVModuleAnalysis.cpp.

https://github.com/llvm/llvm-project/pull/118580