[X86][SSE] Add tests for inserting all-bits (-1) into a vector

We should be able to do this by re-materializing an all-bits vector and then blending with it

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316779 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed