[clang] [CIR] Upstream ShuffleDynamicOp for VectorType (PR #141411)

[Andy Kaylor via cfe-commits]

https://github.com/andykaylor commented:

I have a concern about the masking for the lowering to LLVM IR. Other than that, this looks good.

https://github.com/llvm/llvm-project/pull/141411