[llvm] [RegAlloc] Fix the terminal rule check for interfere with DstReg (PR #168661)

[Quentin Colombet via llvm-commits]

qcolombet wrote:

> > > Do you have a test case that exercises this problem.
> > 
> > 
> > Not for now :)
> 
> I think @qcolombet meant a mir lit test which shows the change, not benchmark results

Yes, that's what I meant :).

https://github.com/llvm/llvm-project/pull/168661