[llvm] [VPlan] Don't convert widen recipes to VP intrinsics in EVL transform (PR #126177)

[Nikolay Panchenko via llvm-commits]

npanchen wrote:

I could easily miss some decision of the EVL vectorizer as I rarely check what's going on there. So if you and  @alexey-bataev @Mel-Chen @arcbbb @ppenzin @preames agreed to come back to proposal to convert instructions to vp-intrinsics after vectorizer that change seems ok.
Otherwise I do see that change a step backward: it's known that at the beginning EVL vectorization won't be perfect and passes such InstCombine need to be updated. But overall hardware that have vl-dependent RVV implementation will benefit of having proper EVL set. 

https://github.com/llvm/llvm-project/pull/126177