swift234

Rework Substitution::subst not to depend on the meaningless 'Archetype' field of Substitutions.

Pass in the context generic parameters that correspond to the substitution vector in Substitution::subst. When we build the type substitution map, also collect the conformances from the substitutions into a map we can use to fill in those conformances in substituted substitutions where necessary, without relying on the '.Archetype' field.

Swift SVN r14964