Pre: add tests for CC constraint intersection.
Pre: add tests for CC constraint intersection.

Also add a failing test for #373.

mozilla/mentat,mozilla/mentat,ncalexan/mentat,mozilla/mentat,ncalexan/mentat,ncalexan/datomish,mozilla/mentat,mozilla/mentat,ncalexan/datomish,ncalexan/mentat,ncalexan/mentat,mozilla/mentat,ncalexan/mentat,ncalexan/mentat