[llvm] [RISCV] Recognize VLA shift pairs from shuffle masks (PR #127710)

[Philip Reames via llvm-commits]

preames wrote:

> @preames I've fixed the warning about captured structured bindings with [609732c](https://github.com/llvm/llvm-project/commit/609732cc2e6572b25ce195cc009e2b4bae42dcda). Thanks!

Thanks!  Your push beat mine by about 2 minutes.  :)

https://github.com/llvm/llvm-project/pull/127710