swift234

In the deserializer, set the archetype for an associated type before
computing its type.  NFC, but it means that dumping the type in the
deubgger while in computeType() works better.

Make sure to set "isrecursive" in ArchetypeBuilder.cpp on an
associated type when the container is found to be recursive even if
we don't emit the diagnostic.  Spotted by inspection, NFC AFAIK.

Enhance the ASTDumper to print the recursive bit on associated types.