swift

c3aa4436 - [Runtime] Fix crash in protocol conformance checks on KVO artificial subclasses.

[Runtime] Fix crash in protocol conformance checks on KVO artificial subclasses. tryGetCompleteMetadataNonblocking crashes on artificial subclasses due to the NULL type descriptor. Explicitly check for artificial subclasses in getSuperclassForMaybeIncompleteMetadata and immediately return their Superclass field. Artificial subclasses are always fully initialized so we don't need to do anything special for them. rdar://72583931