[llvm] IR: Allow vector type in atomic load and store (PR #117625)

[James Y Knight via llvm-commits]

jyknight wrote:

I don't understand why do this in multiple steps? Allow vectors in the verifier and update all of the existing implementations of shouldCastAtomic{Load,Story}InIR to cast vectors at the same time?

https://github.com/llvm/llvm-project/pull/117625