[llvm] [SelectionDAG] Use unaligned store to legalize `EXTRACT_VECTOR_ELT` type when Stack is non-realignable (PR #98176)

[Phoebe Wang via llvm-commits]

https://github.com/phoebewang approved this pull request.

LGTM, thanks!

https://github.com/llvm/llvm-project/pull/98176