swift234

Eliminate getConformsTo() callback from the archetype builder.

The getConformsTo() callback was responsible for forcing the
collection of the requirements directly placed on an associated type,
which then get added to the archetype builder. This resulted in an
unhealthy dependency on the list of protocols attached to TypeDecl
(which should go away). Instead, retrieve the requirements from the
associated type's archetype (once it's been computed) or directly from
its list of "inherited" types (while we're building the generic
signature for the protocol itself).

Swift SVN r31332