[llvm] [X86][GlobalISel] Set Dst register correctly when narrowing G_ICMP (PR #169947)

[Evgenii Kudriashov via llvm-commits]

e-kud wrote:

Actually, the fix in `llvm/lib/Target/X86/GISel/X86LegalizerInfo.cpp` is only required as it starts reproducing the same situation as on RISCV in https://github.com/llvm/llvm-project/pull/119335 -- we stop hitting the branch with `LHSLeftoverRegs`. I just figured out that it most likely a copy paste error, as when we traverse `LHSLeftoverRegs` it makes no sense to test whether it is empty. But then I see legalization issues and once fixed, we stop hitting the `LHSLeftoverRegs` loop.

https://github.com/llvm/llvm-project/pull/169947