tests.haskell*: move into tests.haskell set

This will make it easier to add all haskell related tests to the haskell
hydra jobset without updating a list of tests in two places.

pkgs/test/default.nix

@@ -22,8 +22,7 @@ with pkgs;
   cc-wrapper-libcxx-9 = callPackage ./cc-wrapper { stdenv = llvmPackages_9.libcxxStdenv; };
   stdenv-inputs = callPackage ./stdenv-inputs { };
 
-  haskell-shellFor = callPackage ./haskell-shellFor { };
-  haskell-documentationTarball = callPackage ./haskell-documentationTarball { };
+  haskell = callPackage ./haskell { };
 
   cc-multilib-gcc = callPackage ./cc-wrapper/multilib.nix { stdenv = gccMultiStdenv; };
   cc-multilib-clang = callPackage ./cc-wrapper/multilib.nix { stdenv = clangMultiStdenv; };

pkgs/test/haskell/default.nix

@@ -0,0 +1,6 @@
+{ lib, callPackage }:
+
+lib.recurseIntoAttrs {
+  shellFor = callPackage ./shellFor { };
+  documentationTarball = callPackage ./documentationTarball { };
+}