Revert "SelectionDAG: Enable (and (setcc x), (setcc y)) -> (setcc (and x, y)) for vectors"

This reverts commit r210540, adds a testcase for the regression it
caused, and marks the R600 test it was supposed to fix as XFAIL.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210792 91177308-0d34-0410-b5e6-96231b3b80d8