spec.alpha: (symbol var), Compiler/demunge, MultiFn .dispatchFn/.getMethod, fn .applyTo

General fixes from clojure.spec.alpha's test suite.

- (symbol a-var) returns the var's qualified symbol (clojure.spec.alpha/->sym).
- clojure.lang.Compiler/demunge reverses Clojure's name munging
  ("clojure.core$odd_QMARK_" -> clojure.core/odd?); spec's fn-sym uses it.
- clojure.lang.MultiFn .dispatchFn / .getMethod — spec's multi-spec walks a
  multimethod through them.
- (.applyTo f args) applies a fn to a seq of args (spec instrument).

Most of spec.alpha's conform/explain/describe suite passes. Remaining gaps:
explain-data's :pred for a BARE fn predicate (jolt fns don't carry their defining
symbol, so fn-sym can't recover it), #inst form rendering, and instrument — follow-up.

make test green (+3 corpus rows, 0 new divergences), runtime only (no re-mint).

host/chez/java/dot-forms.ss

@@ -96,6 +96,21 @@
         ;; (.getClass x) universal — the class token for any value, before the
         ;; collection/map field-lookup arms below would read it as a missing key.
         ((string=? method-name "getClass") (jolt-class obj))
+        ;; clojure.lang.MultiFn .dispatchFn / .getMethod — clojure.spec.alpha's
+        ;; multi-spec walks a multimethod through these.
+        ((jolt-multifn? obj)
+         (cond
+           ((string=? mname "dispatchFn") (jolt-multifn-dispatch-fn obj))
+           ((string=? mname "getMethod")
+            (let ((methods (jolt-multifn-methods obj)) (dv (car rest)))
+              (or (hashtable-ref methods dv #f)
+                  (mm-find-isa obj dv)
+                  (hashtable-ref methods (jolt-multifn-default obj) #f)
+                  jolt-nil)))
+           (else (%dot-rmd obj method-name rest-args))))
+        ;; (.applyTo f args): apply a fn to a seq of args (clojure.spec instrument).
+        ((and (procedure? obj) (string=? mname "applyTo"))
+         (apply jolt-invoke obj (seq->list (jolt-seq (car rest)))))
         ;; a transient (ITransientCollection/Set/Map): .contains / .valAt / .count —
         ;; test.check's distinct-collection gen uses (.contains transient-set k).
         ((jolt-transient? obj)