[VPlan] Set correct flags when creating and cloning VPWidenCastRecipe.

Make sure that we set the correct wrap flags when creating new
VPWidenCastRecipes for truncs and preserve the flags from the recipe
directly when cloning, to make sure they are not dropped.

Fixes https://github.com/llvm/llvm-project/issues/160396

GitOrigin-RevId: 70a26da63992142ba2221f1034048ea883cdcb3d
4 files changed