swift234

Move "non-self-conforming protocol type" check out of type validation.

Having semantic checking in type validation introduces the potential for more recursion, triggering crashes. By moving this semantic restriction out to a later stage, we make it more robust. Fixes 6 compiler crashers, although it regressed one compiler crasher that hits a different known issue (assertions in addGenericParameters when we have multiple parameters at the same depth).

Swift SVN r26226