New strategy for compiling the (-> Any Boolean) type to a contract.
When possible, uses `struct-predicate-procedure?` instead of
wrapping in `(-> any-wrap/c boolean?)`.
Makes exceptions for untyped chaperones/impersonators over struct predicates;
those are always wrapped with `(-> any-wrap/c boolean?)`.
This change also affects (require/typed ... [#:struct ...]), but not #:opaque
