[llvm] [MachineLICM] Hoist COPY instruction only when user can be hoisted (PR #81735)

[Rin Dobrescu via llvm-commits]

https://github.com/Rin18 approved this pull request.

The changes make sense to me. @davemgreen might want to take a look as well.

https://github.com/llvm/llvm-project/pull/81735