Merge google -> main (#6323)

* fbfb87a Synchronize submodules with LLVM at llvm/llvm-project@f7b1fa6
* 9714b55 Integrate LLVM at llvm/llvm-project@f7b1fa6
* 3a68d0f Integrate LLVM at llvm/llvm-project@d07f436
* 86fe96a Integrate LLVM at llvm/llvm-project@dcccb2f