[llvm] [mlir] [mlir][transforms]-Extract dead code elimination util (PR #124606)

[River Riddle via llvm-commits]

https://github.com/River707 requested changes to this pull request.

This would be the third place that DCE is accessible, there is already DCE within the regionSimplifiy code as well as the RemoveDeadValues pass. Can you switch to one of those instead?

https://github.com/llvm/llvm-project/pull/124606