[llvm] [LSR] Fix matching vscale immediates (PR #100080)

[Benjamin Maxwell via llvm-commits]

MacDue wrote:

Note: The first commit in this PR [Precommit vscale-fixups.ll test](https://github.com/llvm/llvm-project/commit/b72ad834080ba31b9de566304d3deece81fdb0ad) shows the current (incorrect) codegen. 

https://github.com/llvm/llvm-project/pull/100080