[X86] Adding a test for vector shuffle extractions.

When both the vector inputs of the shuffle vector is comprising of same vector or shuffle mask is accessing elements from only one operand vector (like in PR33758 test already present).

Committed on behalf of @jbhateja (Jatin Bhateja)

Differential Revision: https://reviews.llvm.org/D36271

llvm-svn: 309963