[X86] Add baseline test for "odd" shuffles. NFC.

Adds a baseline test for lowering shuffles where the width of the output
vector is not twice the size of the input vectors. Many of those sequences
are suboptimal, and will hopefully be improved in follow-up patches.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@279888 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed