Integrate LLVM at llvm/llvm-project@0820c6ef6038
Integrate LLVM at llvm/llvm-project@0820c6ef6038

Updates LLVM usage to match
[0820c6ef6038](https://github.com/llvm/llvm-project/commit/0820c6ef6038)

PiperOrigin-RevId: 475283550

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