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

[Sander de Smalen via llvm-commits]

https://github.com/sdesmalen-arm commented:

> I am not sure if it is possible to construct one at the moment, due to various restrictions for early-exit vectorization. Not generating the extract for a vector VF included in the range would lead to a silent mis-compile, as without clamping the range we cannot guarantee that the vector VF would not be selected.

Fair enough, thanks for explaining!

Left just one more nit, but otherwise LGTM.

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