[x86] Teach the new vector shuffle lowering to use the AVX VPERMILPS
instruction for single-vector floating point shuffles. This in turn
allows the shuffles to fold a load into the instruction which is one of
the common regressions hit with the new shuffle lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218190 91177308-0d34-0410-b5e6-96231b3b80d8
Update tests which broke from r218189

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218191 91177308-0d34-0410-b5e6-96231b3b80d8
[x86] Add an AVX run to the 128-bit v2 tests, teach them to have
a generic SSE and AVX mode in addition to a specific AVX1 test path, and
flesh out the AVX tests.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@218192 91177308-0d34-0410-b5e6-96231b3b80d8