haskellPackages.stan: Mark as not broken and enable tests

With https://github.com/NixOS/nixpkgs/pull/101008, this package builds
successfully and passes all tests as well.

pkgs/development/haskell-modules/configuration-common.nix

@@ -1322,10 +1322,6 @@ self: super: {
   # Upstream issue: https://github.com/kowainik/trial/issues/62
   trial = doJailbreak super.trial;
 
-  # 2020-06-24: Tests are broken in hackage distribution.
-  # See: https://github.com/kowainik/stan/issues/316
-  stan = dontCheck super.stan;
-
   # 2020-06-24: Tests are broken in hackage distribution.
   # See: https://github.com/robstewart57/rdf4h/issues/39
   rdf4h = dontCheck super.rdf4h;

pkgs/development/haskell-modules/configuration-hackage2nix.yaml

@@ -10077,7 +10077,6 @@ broken-packages:
   - stackage-types
   - stackage-upload
   - stackage2nix
-  - stan
   - standalone-derive-topdown
   - standalone-haddock
   - starling