Fix tyConToIfaceDecl (Trac #9190)
There are three bugs here, one serious * We were failing to tidy the type arguments in an IfTyConParent This is what was causing Trac #9190. * toIfaceTcArgs is careful to suppress kind arguments, but there was a clone, tidyToIfaceTcArgs in IfaceSyn which didn't. Now the latter goes via the former. * When pretty-printing a IfaceDecl for an algebraic data type, and doing so in Haskell-98 syntax, we were silently assuming that the universal type variables of the TyCon and the DataCon were the same. But that has not been true for some time. Result: a very confusing display. Solution: during the conversion to IfaceSyn, take the opportunity to make the universal type variables line up exactly. This is very easy to do, makes the pretty-printing easy, and leaves open the future possiblity of not serialising the universal type variables of the data constructor.