Small maps preserve insertion order

jolt maps were HAMTs with hash iteration order; Clojure keeps small maps as
PersistentArrayMap (insertion order), converting to PersistentHashMap past a
threshold. Map literals, array-map, assoc, into/transient, merge, zipmap,
select-keys, update-keys/vals, frequencies and group-by now iterate in insertion
order for <=8 entries, matching the JVM. hash-map and >8-entry maps stay hash
order; sets stay hash order.

The pmap record gains an order field (the insertion-order key list, or #f once
hashed); the HAMT still backs the values so equality/hash/lookup are unchanged.
pmap-fold visits an array-mode map last-to-first so the runtime's cons-accumulate
idiom reconstructs insertion order without touching its many call sites, and
hash-mode output stays byte-identical; pmap-fold-fwd visits in order for the few
sites that build a value directly. Transient maps track insertion order and
promote to hash past max(8, source-count), matching TransientArrayMap.

The hash-map native-op retargets to a hash-order builder so (hash-map ...) stays
hash-ordered while {...} literals are ordered; syntax-quote builds maps via the
hash builder (Clojure expands `{...} to apply hash-map). The core overlay map
builders seed from {} instead of (hash-map) to keep order.

Threshold is 8 for any key (the keyword exception in newer Clojure isn't in
1.12.5). honeysql now passes 832/0/0; 19 JVM-certified corpus rows added.

jolt-core/jolt/backend_scheme.clj

@@ -23,7 +23,7 @@
    "=" "jolt=" "inc" "jolt-inc" "dec" "jolt-dec" "not" "jolt-not"
    "min" "min" "max" "max"
    "mod" "modulo" "rem" "remainder" "quot" "quotient"
-   "vector" "jolt-vector" "hash-map" "jolt-hash-map" "hash-set" "jolt-hash-set"
+   "vector" "jolt-vector" "hash-map" "jolt-hash-map-fn" "hash-set" "jolt-hash-set"
    "conj" "jolt-conj" "get" "jolt-get" "nth" "jolt-nth" "count" "jolt-count"
    "assoc" "jolt-assoc" "dissoc" "jolt-dissoc" "contains?" "jolt-contains?"
    "empty?" "jolt-empty?" "peek" "jolt-peek" "pop" "jolt-pop"