[llvm] [LV] Check if the VF is scalar by VFRange instead of VPlan in `handleUncountableEarlyExit` NFC. (PR #135294)

[Sander de Smalen via llvm-commits]

https://github.com/sdesmalen-arm approved this pull request.

Thanks! LGTM with nit addressed.

https://github.com/llvm/llvm-project/pull/135294