Adjust expected failures
The GHC issue that caused JuicyPixels to fail (ghc#17590 (closed)) has
been fixed, so JuicyPixels can be removed from the list of expected
failures.
The original issue that caused free-algebras to fail
(ghc#17710 (closed)) has been fixed, but a new issue has taken its place
(ghc#16502 (comment 259055)). I've
changed the expected failure reason accordingly.
singletons now fails on HEAD due to ghc#17923 (closed), so this patch
also adds it as an expected failure.
Edited by Ryan Scott