[llvm] [AArch64] Assert "Request for a fixed element count on a scalable obect" (PR #105484)

[Florian Hahn via llvm-commits]

https://github.com/fhahn commented:

For the title, might be better to use something like `[AArch64] Bail out for scalable vecs in areExtractShuffleVectors`

https://github.com/llvm/llvm-project/pull/105484