feat: add missing core fns (bit-clear, get-method, second, predicates, ...)

Resolve symbols that were unbound or leaking to broken Janet builtins:
- bit-clear/bit-set/bit-flip/bit-test/bit-and-not
- get-method/methods (multimethod introspection)
- second/ffirst/nfirst/fnext/nnext, last (was leaking to Janet, broke on pvec),
  drop-last/take-last
- ident?/simple-symbol?/qualified-keyword?/simple-keyword?/simple-ident?/
  qualified-ident?/inst?/inst-ms/uri?/uuid?/bytes?/tagged-literal?
- clojure.string/re-quote-replacement

Advances the SCI bootstrap; conformance 206/206, features 71/71.

src/jolt/clojure/string.clj

@@ -121,3 +121,13 @@
    (let [sub (subs s 0 from) r (str-reverse-b sub) sval (str-reverse-b value)
          idx (str-find sval r)]
      (when idx (inc (- from (+ idx (count value))))))))
+
+(defn re-quote-replacement
+  "Escape special characters (backslash and dollar) in a regex replacement
+  string so it is used literally rather than interpreted."
+  [replacement]
+  (apply str
+    (map (fn [ch]
+           (let [c (str ch)]
+             (if (or (= c "\\") (= c "$")) (str "\\" c) c)))
+         (seq replacement))))