[Bug d/89418] D test cases fail on powerpc64le

[ibuclaw at gdcproject dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89418

--- Comment #5 from Iain Buclaw <ibuclaw at gdcproject dot org> ---
For now, I've the tests will return UNSUPPORTED, as they depend on full
libphobos support that powerpc* targets simply don't have (because of
incomplete or lacking any support in std.math and std.internal.gammafunctions).