Run core.memoize's test suite on jolt

Shaking out clojure.core.memoize (207 assertions, 0 fail) cleared several
general gaps:

- deref/@ on a deftype or reify implementing clojure.lang.IDeref dispatches to
  its deref method (RetryingDelay / make-derefable).
- deftype mutable fields (^:unsynchronized-mutable / ^:volatile-mutable) are
  read live: a set! within a method is observed by a later read in the same
  invocation, not the entry-time capture. Needed for double-checked locking.
  Immutable fields stay let-bound. Field reads rewrite to (.-field inst) with
  lexical-shadow tracking.
- def metadata values are evaluated, like Clojure: ^{:k (f)} stores (f)'s
  result and ^{:af some-fn} the fn. :tag stays a literal hint.
- try dispatches catch clauses by class in order via the exception supertype
  hierarchy; a non-matching value re-throws, an untyped host condition is caught
  by a RuntimeException/Exception/Throwable clause. Previously the last clause
  won and the class was ignored.
- locking takes a real per-object monitor (recursive Chez mutex) now that
  futures/agents/threads share one heap; it was a no-op.
- supers/ancestors reflect a small modeled JVM interface hierarchy, so
  (ancestors (class f)) yields Runnable/Callable (core.memoize's arg check).
- AssertionError / Error constructors.

JOLT_FEATURES is gone from the docs: it isn't read anywhere on Chez, and the
reader already includes :clj in its default feature set. RFC 0002's
{:jolt :default} design was reverted in the reader; docs now match the code.

Raises the SCI floor 205 -> 210.

jolt-core/clojure/core/21-coll.clj

@@ -344,8 +344,12 @@
 (defn numerator [x] (throw (ex-info "numerator requires a ratio (Jolt has no ratios)" {})))
 (defn denominator [x] (throw (ex-info "denominator requires a ratio (Jolt has no ratios)" {})))
 
-;; No class hierarchy on this host.
-(defn supers [x] #{})
+;; jolt has no reflection, but a few common JVM interfaces carry a modeled
+;; ancestry (jolt.host/class-supers) so reflective checks like
+;; (ancestors (class f)) answer like the JVM.
+(defn supers [x]
+  (let [s (jolt.host/class-supers x)]
+    (if s (set s) #{})))
 
 ;; Like Clojure's munge: rewrite dashes to underscores, preserving the argument's
 ;; type — a symbol munges to a symbol, anything else to a string. (jolt only