[CSBindings] Make infer* methods private to PotentialBindings

Author: xedin

lib/Sema/ConstraintSystem.h

@@ -4582,6 +4582,7 @@ class ConstraintSystem {
     /// if it has only concrete types or would resolve a closure.
     bool favoredOverDisjunction(Constraint *disjunction) const;
 
+private:
     /// Detect `subtype` relationship between two type variables and
     /// attempt to infer supertype bindings transitively e.g.
     ///
@@ -4604,6 +4605,7 @@ class ConstraintSystem {
     void inferDefaultTypes(ConstraintSystem &cs,
                            llvm::SmallPtrSetImpl<CanType> &existingTypes);
 
+public:
     /// Finalize binding computation for this type variable by
     /// inferring bindings from context e.g. transitive bindings.
     void finalize(ConstraintSystem &cs,