Fix general divergences surfaced by clojure-test-suite

Five fixes shaken out by running jank-lang/clojure-test-suite:

- = short-circuits on identity like Util.equiv's k1 == k2, so (= s s) on an
  infinite lazy seq answers true instead of walking forever. Numbers keep the
  exactness-aware arm ((= ##NaN ##NaN) stays false like the JVM's).
- Calling a non-fn names the operator's CLASS in the ClassCastException, like
  the JVM — never the value, whose printed form may be unbounded: ((range))
  must throw, not hang rendering an infinite seq.
- realized? on a seq cell answers by its forced flag (the rest of a realized
  lazy chain is a cseq under jolt's seq model), and the overlay's unsupported-
  type error names the class, not the (possibly infinite) value.
- clojure.test/is dispatches a REGISTERED assert-expr method before its by-name
  inline paths, like clojure.test where the built-ins are just pre-registered
  methods — so an alias-qualified p/thrown? (the suite's portability helper)
  isn't captured by the built-in thrown? path, which read its body as a class.
- clojure.test tracks tests and fixtures per namespace: deftest records its
  defining ns, use-fixtures registers under the calling ns (no more cross-ns
  clobbering), (run-tests 'ns ...) runs only those namespaces like clojure.test,
  and each run-tests call prints/returns its own summary (global counters stay
  cumulative for the n-pass/n-fail harness API).

Re-mint (20-coll.clj is seed; prelude only). +2 JVM-certified corpus rows;
the clojure-test fixture pins the alias-qualified assert-expr, per-call
summaries, and ns filtering.

test/chez/corpus.edn

@@ -3513,4 +3513,6 @@
   {:suite "reduce / IReduceInit" :label "a deftype reduce honors reduced short-circuit" :expected "3" :actual "(do (deftype Rng [n] clojure.lang.IReduceInit (reduce [_ f init] (loop [i 0 acc init] (if (< i n) (let [a (f acc i)] (if (reduced? a) @a (recur (inc i) a))) acc)))) (reduce (fn [acc x] (if (= x 3) (reduced acc) (+ acc x))) 0 (->Rng 10)))"}
   {:suite "exceptions / typed throw" :label "a jolt-raised NumberFormatException reports its real class and message" :expected "[\"java.lang.NumberFormatException\" \"For input string: \\\"xyz\\\"\"]" :actual "(try (Long/parseLong \"xyz\") (catch Throwable e [(.getName (class e)) (.getMessage e)]))"}
   {:suite "exceptions / hierarchy catch" :label "a typed throwable matches its superclasses, not unrelated ones" :expected "[true true true false]" :actual "(let [e (try (Long/parseLong \"z\") (catch Throwable e e))] [(instance? NumberFormatException e) (instance? IllegalArgumentException e) (instance? Exception e) (instance? java.io.IOException e)])"}
+  {:suite "equality / identity" :label "= short-circuits on identity without realizing a lazy seq (Util.equiv k1 == k2)" :expected "0" :actual "(let [n (atom 0) s (map (fn [x] (swap! n inc) x) [1 2 3])] (= s s) @n)"}
+  {:suite "realized? / lazy seq" :label "realized? reads a lazy seq's realization flag" :expected "[false true]" :actual "(let [s (map inc [1 2 3])] [(realized? s) (do (doall s) (realized? s))])"}
 ]