Revert "Revert r184787: "Added arm_neon intrinsic tests.""

This reverts commit r184817. The failure Chandler was seeing was most likely the
bug that Bob Wilson fixed in r184870 (which was a bug caught by these tests).

To be safe, I just checked again on x86-64 mac os x/linux that this test passed
(which it did).

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@185110 91177308-0d34-0410-b5e6-96231b3b80d8