Re-add SystemZ SNaN test

The floating-point bug affecting ninja-x64-msvc-RA-centos6 is fixed (r277813) so this test should
now pass


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@278034 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed