core: set PROVIDER type as Persistent class id

Pass along the PROVIDER type, that is already passed to AsyncWrap, along
to BaseObject to set the handle_'s class id. This will allow all
Persistents to be transversed and uniquely identified by what type they
are using APIs such as v8::PersistentHandleVisitor.

PR-URL: https://github.com/nodejs/io.js/pull/1730


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>