In this change, moved following function from LoopVectorizer to VectorUtils:
a) getGEPInductionOperand b) stripGetElementPtr c) getUniqueCastUse d) getStrideFromPointer
These functions are common between loop vectorizer & upcoming loop versioning for LICM.
Earlier these functions are defined as static functions in LoopVectorize.cpp
For re-usability its good to keep them as utility.
Please sort these.