[llvm] [M68k] Prevent COPY instruction from killing live condition flags (PR #168485)

[Dan Salvato via llvm-commits]

dansalvato wrote:

@knickish Thank you, I resolved conflicts and rebased with a force push to remove that one obsolete merge commit I had in the branch.

Once this is merged, I'll open a new issue to continue the discussion on how we can better solve this.

https://github.com/llvm/llvm-project/pull/168485