[CostModel]Replace FixedVectorType by VectorType in costgetIntrinsicInstrCost

This patch replaces FixedVectorType by VectorType in getIntrinsicInstrCost
in BasicTTIImpl.h. It re-arranges the scalable type test earlier return
and add tests for scalable types.

Depends on D91532

Differential Revision: https://reviews.llvm.org/D92094