[llvm] [GlobalISel] Lower G_SHUFFLE_VECTOR with scalar result (PR #65275)

[Jay Foad via llvm-commits]

jayfoad wrote:

> I'm surprised this is legal

I guess because IR shuffle is allowed on `<1 x type>` vectors, and LLT uses scalars instead of 1-element vectors.

https://github.com/llvm/llvm-project/pull/65275