[x86] Add some tests for specific patterns of lane-flips combined with
in-lane shuffles that aren't always handled well by the current vector
shuffle lowering.

No functionality change yet, that will follow in a subsequent commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221938 91177308-0d34-0410-b5e6-96231b3b80d8