[X86] Update X86InstCombineIntrinsic to use CreateShuffleVector with one vector

This patch updates X86InstCombineIntrinsic.cpp to use the newly updated CreateShuffleVector.

The tests are updated because the updated CreateShuffleVector uses poison value for the second vector.
If I didn't miss something, the masks in the tests are choosing elements from the first vector only; therefore the tests are having equivalent behavior.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D94059