swift234

Allow TypeLocs as parameters to diagnostics.

Eventually TypeLocs coming from the Parser will contain only a TypeRepr and the TypeChecker will resolve and add the type.
Passing a TypeLoc to a diagnostic means "print as user written" (even before typechecking)
and if there is no TypeRepr (e.g. due to a TypeLoc coming from a module without location info) print the type.

Swift SVN r6280