[SLP]Remove CreateShuffle lambda and reuse ShuffleBuilder functions.

After merging main part of the gather/buildvector code, CreateShuffle
lambda can removed and ShuffleBuilder add functions can be used instead.
Also, part of the code from CreateShuffle migrated to createShuffle of
the BaseShuffleAnalysis::createShuffle function for better code emission.

Differential Revision: https://reviews.llvm.org/D145988