[clang] [llvm] [SROA] Use constant 64-bit indices for Extract/InsertElement (PR #208918)

[Yonah Goldberg via cfe-commits]

https://github.com/YonahGoldberg commented:

We should probably update these while we're at it

https://github.com/llvm/llvm-project/blob/9d5d8834793da9efe297620db3ef39633688f830/llvm/lib/IR/Instructions.cpp#L1757

<img width="541" height="74" alt="Image" src="https://github.com/user-attachments/assets/be49b1c1-405e-418e-a0d6-e2927e209737" />

<img width="658" height="84" alt="Image" src="https://github.com/user-attachments/assets/fd796ee6-0430-44e0-8261-1e2490fadc87" />

https://github.com/llvm/llvm-project/pull/208918