[llvm] [RegisterCoalescer] The COPY with the implicit-def of super register is not coalescable. (PR #169997)

[Benjamin Maxwell via llvm-commits]

MacDue wrote:

Is this change needed given https://github.com/llvm/llvm-project/pull/168353 was reverted (again)? 

https://github.com/llvm/llvm-project/pull/169997