Object as a concrete class

[Kevin Bourrillion]

So either way, I'd still really want for `new Object()` to get a warning,
and for Object to eventually become literally abstract (how long from now,
I don't as much care). Why: the fact that Object isn't abstract actually
detracts from people's understanding of both abstractness and Object. By
rights it should be; abstract means lacking, and it's lacking any
distinguishable type or behavior.

Could we? Do that?

If we can, then does it matter as much what we do here? It seems to me that
most people will fix the warning like: `new Object() {}`, and good on them,
but we could just do something roughly equivalent for them until they do...