Integrate LLVM at llvm/llvm-project@b5d6ad20e182
Integrate LLVM at llvm/llvm-project@b5d6ad20e182

Updates LLVM usage to match
[b5d6ad20e182](https://github.com/llvm/llvm-project/commit/b5d6ad20e182)

PiperOrigin-RevId: 401501817

google-research/structured-additive-IR,google-research/structured-additive-IR