Fix six JVM divergences surfaced by rewrite-clj

Running the rewrite-clj test suite under jolt exposed six bugs, each fixed here:

- `for`/`doseq` `:let` bindings never went through `destructure`, so a
  destructuring pattern (`:let [{:keys [y]} x]`) hit `let*` raw and failed to
  compile. Emit `let`, like Clojure.
- `with-open` couldn't close a deftype/defrecord that implements a `close` method
  (java.io.Closeable / AutoCloseable, e.g. tools.reader's readers) — `__close`
  only knew jhost readers and map `:close` fns. Dispatch a record's `close`.
- A deftype/defrecord method param named like a field didn't shadow the field
  (the field's let-binding wrapped the params). Params now shadow, as in Clojure.
- A deftype whose simple name collided with a built-in host class clobbered it in
  the global ctor table, so `(java.io.PushbackReader. …)` built tools.reader's
  same-named deftype. Register deftypes/built-ins by FQN, don't let a deftype
  overwrite a built-in's simple name, and qualify a bare `(Name. …)` to the
  deftype's FQN only in the ns that defined it.
- `clojure.walk` was lazy over a non-list seq (missing `doall`), so a walk whose
  fn has side effects read stale state. Make it eager, like Clojure.
- `Character/isWhitespace` used an ASCII-only check that missed U+2028 and other
  Unicode whitespace. Use the JVM's Unicode set (minus the no-break spaces it
  excludes).

Regressions: corpus rows (for-let destructure, method-param shadow, walk eager,
isWhitespace), a unit row (with-open closes a record), and smoke checks (the
class-name collision, run in a fresh -e process so the deftype doesn't leak).

One divergence remains unfixed: a submatch from a losing regex alternation branch
leaks when the winning branch has a quantified group (a bug in the vendored
irregex engine, not jolt) — tracked separately.

jolt-core/clojure/core/00-syntax.clj

@@ -514,7 +514,9 @@
                             sub (wrap-mods (rest mods) inner)]
                         (if (= (first m) :when)
                           `(if ~(nth m 1) ~sub [])
-                          `(let* ~(nth m 1) ~sub)))))
+                          ;; `let` (not let*) so a :let binding may itself
+                          ;; destructure — (for [x xs :let [{:keys [y]} x]] …).
+                          `(let ~(nth m 1) ~sub)))))
         build (fn build [idx groups]
                 (let [g (nth groups idx)
                       my-bind (nth g 0)

jolt-core/clojure/core/30-macros.clj

@@ -385,11 +385,18 @@
                     ;; field binds / live-read instance (see defrecord's mk-clause).
                     (let [argv (mapv (fn [p] (if (= p (quote _)) (gensym "_p") p)) (nth spec 1))
                           inst (first argv)
+                          ;; A method param shadows a same-named field (Clojure
+                          ;; semantics): don't let-bind a field the param already
+                          ;; provides, and treat those params as shadowing so a
+                          ;; mutable field's live-read rewrite doesn't override them.
+                          pnames (set (map name argv))
                           ;; let-bind only immutable fields; mutable ones are read live
                           ;; via rewrite-body so a set! within the method is observed.
                           binds (vec (mapcat (fn [f] [f `(get ~inst ~(keyword (name f)))])
-                                             (filter (fn [f] (not (mutable? f))) fields)))
-                          mbody (map (fn [bf] (rewrite-body inst #{} bf)) (drop 2 spec))]
+                                             (filter (fn [f] (and (not (mutable? f))
+                                                                  (not (contains? pnames (name f)))))
+                                                     fields)))
+                          mbody (map (fn [bf] (rewrite-body inst (set argv) bf)) (drop 2 spec))]
                       (list argv (list* 'let binds mbody))))
         groups (group-by-head body)
         ;; merge clauses by method NAME across ALL protocols into one multi-arity
@@ -616,7 +623,11 @@
                     (let [argv (mapv (fn [p] (if (= p (quote _)) (gensym "_p") p)) (nth spec 1))
                           inst (first argv)
                           hinted (assoc argv 0 (vary-meta inst assoc :tag (name name-sym)))
-                          binds (vec (mapcat (fn [f] [f `(get ~inst ~(keyword (name f)))]) fields))]
+                          ;; a method param shadows a same-named field (Clojure
+                          ;; semantics), so don't rebind a field the param provides.
+                          pnames (set (map name argv))
+                          binds (vec (mapcat (fn [f] [f `(get ~inst ~(keyword (name f)))])
+                                             (remove (fn [f] (contains? pnames (name f))) fields)))]
                       (list hinted (list* 'let binds (drop 2 spec)))))
         groups (group-by-head body)
         ;; merge clauses by name across protocols into one multi-arity fn (see