Integrate LLVM at llvm/llvm-project@8efa6512e066
Integrate LLVM at llvm/llvm-project@8efa6512e066

Updates LLVM usage to match
[8efa6512e066](https://github.com/llvm/llvm-project/commit/8efa6512e066)

PiperOrigin-RevId: 403977237

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