json_tokener, arraylist: assorted cleanups

json_tokener.c assigned to an int64_t through a (uint64_t) cast.  The
guarded range makes it harmless, but the cast names the wrong type.

array_list_expand_internal() reallocated when max == arr->size even though
the array can already hold max entries at that point, since callers only
index up to max - 1.  Skip the realloc.

arraylist.c

@@ -83,7 +83,10 @@ static int array_list_expand_internal(struct array_list *arr, size_t max)
 	void *t;
 	size_t new_size;
 
-	if (max < arr->size)
+	/* The array can already hold max entries when max == arr->size, since
+	 * the caller only ever indexes up to max - 1.
+	 */
+	if (max <= arr->size)
 		return 0;
 	/* Avoid undefined behaviour on size_t overflow */
 	if (arr->size >= SIZE_T_MAX / 2)

json_tokener.c

@@ -1157,7 +1157,7 @@ struct json_object *json_tokener_parse_ex(struct json_tokener *tok, const char *
 					}
 					if (numuint64 <= INT64_MAX)
 					{
-						num64 = (uint64_t)numuint64;
+						num64 = (int64_t)numuint64;
 						current = json_object_new_int64(num64);
 						if (current == NULL)
 						{