The patch adds EVL member into InterestingMemoryOperand for vp load/store support.

The patch adds new member MaybeEVL into InterestingMemoryOperand to represent the effective vector length for vp intrinsics. It may be extended for some target intrinsics in the feature.

The patch adds EVL member into InterestingMemoryOperand for vp load/store supportnew member MaybeEVL into InterestingMemoryOperand to represent the effective vector length for vp intrinsics. It may be extended for some target intrinsics in the feature.