Integrate LLVM at llvm/llvm-project@862fffd8231c
Integrate LLVM at llvm/llvm-project@862fffd8231c

Updates LLVM usage to match
[862fffd8231c](https://github.com/llvm/llvm-project/commit/862fffd8231c)

PiperOrigin-RevId: 419449865

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