(incomplete) support for consructor reflection
pretty stupid - this is almost identical to Method, but we can't derive,
and the delegation happens at the peer level anyways.
NOTE: 'regIdx' and 'name' need to be like Method, or the peer delegation
fails (this is the hack'ish part)
NOTE: we ditch the 'final' modifier so that we can provide our
own serialization ctor objects - that's probably going away
once we replace ObjectStreamClass