Integrate LLVM at llvm/llvm-project@a4afa2bde6f4
Integrate LLVM at llvm/llvm-project@a4afa2bde6f4

Updates LLVM usage to match
[a4afa2bde6f4](https://github.com/llvm/llvm-project/commit/a4afa2bde6f4)

PiperOrigin-RevId: 479769053

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