Integrate LLVM at llvm/llvm-project@67dfe9c8d70c
Integrate LLVM at llvm/llvm-project@67dfe9c8d70c

Updates LLVM usage to match
[67dfe9c8d70c](https://github.com/llvm/llvm-project/commit/67dfe9c8d70c)

PiperOrigin-RevId: 355235205

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