swift234

Teach IRGen's archetype uniquing to handle same-type constraints more generally.

Archetype uniquing was not accounting for the presence of archetypes
within the concrete types of nested types, e.g., where Self.Foo ==
X<T>. Extend the profiling used in archetype uniquing to handle such
cases by profiling all of the canonical types directly. Fixes
rdar://problem/21665983.

Swift SVN r29946