Pattern Matching for instanceof (Preview 2)

[Brian Goetz]

> var is not really any, it's an inferred type pattern.
> '_' is any, no ?

Conveniently, an inferred type pattern _is_ an any pattern.  (See the 
explanation in the recent discussion on nullity, where this fell out 
nicely.)   So semantically a var pattern is an any pattern. Whether or 
not we want an explicit any pattern is a separate question.