[llvm] [LV]: Improve accuracy of calculating remaining iterations of MainLoopVF (PR #156723)

[Hassnaa Hamdi via llvm-commits]

hassnaaHamdi wrote:

I think this patch is not needed now as https://github.com/llvm/llvm-project/pull/157836 is landed. SCEV now can evaluate vscale-based expressions.

https://github.com/llvm/llvm-project/pull/156723