swift234

Centralize the creation/lookup of normal protocol conformances further.

This simplifies and isolates the "deep conformance checking" behavior
of LazyResolver::checkConformance (renamed from
LazyResolver::resolveConformance). We actually don't want to be
triggering this from lookup, because it's exceedingly non-lazy, but
our lazy resolution of witnesses isn't good enough to support that
just yet. NFC

Swift SVN r26319