Stop attempting to "trim" data types in interface files
Without -O, we previously tried to make interface files smaller by not including the data constructors of data types. But there are a lot of exceptions, notably when Template Haskell is involved or, more recently, DataKinds. However Trac #7445 shows that even without TemplateHaskell, using the Data class and invoking Language.Haskell.TH.Quote.dataToExpQ is enough to require us to expose the data constructors. So I've given up on this "optimisation" -- it's probably not important anyway. Now I'm simply not attempting to trim off the data constructors. The gain in simplicity is worth the modest cost in interface file growth, which is limited to the bits reqd to describe those data constructors.