Fix 4 clojure.core bugs surfaced by JVM certification

The corpus certifier (test/conformance) flagged four cases where jolt's
hand-written :expected matched a real defect rather than Clojure. Fixed in the
jolt-core overlay, corrected the spec :expected, re-certified against JVM Clojure:

- ex-message: returns nil for a non-throwable (dropped the lenient string branch);
  still returns the message for ex-info. (jolt-l8e8)
- munge: preserves the argument's type — a symbol munges to a symbol, not a string.
  (jolt-hc35)
- print: (print nil) emits "nil", not "" (top-level nil guard; str yields "").
  (jolt-pqio)
- bounded-count: uses the counted? fast path (full count), else counts up to n via
  seq — was (min n (count coll)), wrong for counted colls. Added an uncounted-coll
  spec case. (jolt-2507)

Removed the 4 :bug entries from known-divergences.edn (now certified), regenerated
corpus + profile, re-minted the Chez bootstrap seed (clojure.core changed). Gates:
Janet 155/0, JVM certify clean, both Chez corpus gates 2534 (floors raised),
bootstrap 6/6, fixpoint intact.

test/spec/exceptions-spec.janet

@@ -43,4 +43,4 @@
    "(try (try (throw (ex-info \"inner\" {})) (catch :default e (throw e))) (catch :default e (ex-message e)))"]
   ["ex-data on non-ex"    "nil"       "(ex-data 42)"]
   ["ex-cause on non-ex"   "nil"       "(ex-cause {:k 1})"]
-  ["ex-message of string" "\"hi\""    "(ex-message \"hi\")"])
+  ["ex-message of string" "nil"        "(ex-message \"hi\")"])

test/spec/functions-spec.janet

@@ -58,7 +58,7 @@
   ["denominator throws"  :throws    "(denominator 1)"]
   ["supers empty set"    "#{}"      "(supers 1)"]
   ["munge dashes"        "\"a_b\""  "(munge \"a-b\")"]
-  ["munge symbol"        "\"x_y\""  "(munge (quote x-y))"]
+  ["munge symbol"        "(quote x_y)"  "(munge (quote x-y))"]
   ["test no-test"        ":no-test" "(test (quote foo))"])
 
 # Phase 2 leaf batch 2 (jolt-ded): canonical ports of key/val/select-keys/

test/spec/io-spec.janet

@@ -65,7 +65,7 @@
   ["println appends newline" "\"x 1\\n\"" "(with-out-str (println \"x\" 1))"]
   ["prn is readable + newline" "\"[1 \\\"s\\\"]\\n\"" "(with-out-str (prn [1 \"s\"]))"]
   ["pr writes no newline" "\"\\\\a\"" "(with-out-str (pr \\a))"]
-  ["print nil arg"      "\"\""        "(with-out-str (print nil))"]
+  ["print nil arg"      "\"nil\""     "(with-out-str (print nil))"]
   ["prn keyword"        "\":k\\n\""   "(with-out-str (prn :k))"])
 
 # print-method is a real multimethod (jolt-g1r): canonical dispatch on

test/spec/sequences-spec.janet

@@ -238,7 +238,8 @@
   ["drop-last n"               "[1 2]"  "(drop-last 2 [1 2 3 4])"]
   ["split-with"                "[[2 4] [5 6]]" "(split-with even? [2 4 5 6])"]
   ["replicate"                 "[:x :x :x]" "(replicate 3 :x)"]
-  ["bounded-count"             "3"      "(bounded-count 3 [1 2 3 4 5])"]
+  ["bounded-count"             "5"      "(bounded-count 3 [1 2 3 4 5])"]
+  ["bounded-count uncounted"   "3"      "(bounded-count 3 (filter odd? (range 100)))"]
   ["run! side effects"         "6"      "(let [a (atom 0)] (run! (fn [x] (swap! a + x)) [1 2 3]) @a)"]
   ["completing wraps rf"       "3"      "((completing +) 1 2)"]
   ["comparator <"              "[1 2 3]" "(sort (comparator <) [3 1 2])"]