[VPlan] Handle Mul/UDiv in getSCEVExprForVPValue (NFCI).
Support Mul/UDiv and AND-variant (https://alive2.llvm.org/ce/z/rBJVdg)
in getSCEVExprForVPValue.
This is used in code paths when computing SCEV expressions in the
VPlan-based cost model, which should produce costs matching the legacy
cost model.
