[VPlan] Add VPRecipeBase::mayHaveSideEffects.

Add an initial version of a helper to determine whether a recipe may
have side-effects.

Reviewed By: a.elovikov

Differential Revision: https://reviews.llvm.org/D100259

GitOrigin-RevId: 6adebe3fd2914f1f87e8e984d1bf17639b119a89
3 files changed