js-on-sx: js-new-call accepts list-typed constructor returns

new Array(1,2,3) was returning an empty wrapper object because
js-new-call only honoured a non-undefined return when
(type-of ret) === "dict"; SX lists (representing JS arrays) were
silently discarded. Widened the check to accept "list" too.
Fixes new Array(1,2,3).length, String(new Array(1,2,3)), and any
constructor whose body returns a list. built-ins/String:
67/99 → 69/99 (canonical). conformance.sh: 148/148.

lib/js/runtime.sx

@@ -624,7 +624,9 @@
         (let
           ((ret (js-call-with-this obj ctor args)))
           (if
-            (and (not (js-undefined? ret)) (= (type-of ret) "dict"))
+            (and
+              (not (js-undefined? ret))
+              (or (= (type-of ret) "dict") (= (type-of ret) "list")))
             ret
             obj))))))