js-on-sx: js-new-call honours function-typed constructor returns

new Object(func) should return func itself (per ES spec - "if value
is a native ECMAScript object, return it"), but js-new-call only
kept the ctor's return when it was dict or list — functions fell
through to the empty wrapper. Added (js-function? ret) to the
accept set.
built-ins/Object: 42/50 → 44/50. conformance.sh: 148/148.

lib/js/test262-scoreboard.json

@@ -1,61 +1,45 @@
 {
   "totals": {
-    "pass": 78,
-    "fail": 15,
-    "skip": 1,
-    "timeout": 6,
-    "total": 100,
-    "runnable": 99,
-    "pass_rate": 78.8
+    "pass": 44,
+    "fail": 6,
+    "skip": 0,
+    "timeout": 0,
+    "total": 50,
+    "runnable": 50,
+    "pass_rate": 88.0
   },
   "categories": [
     {
-      "category": "built-ins/String",
-      "total": 100,
-      "pass": 78,
-      "fail": 15,
-      "skip": 1,
-      "timeout": 6,
-      "pass_rate": 78.8,
+      "category": "built-ins/Object",
+      "total": 50,
+      "pass": 44,
+      "fail": 6,
+      "skip": 0,
+      "timeout": 0,
+      "pass_rate": 88.0,
       "top_failures": [
-        [
-          "Test262Error (assertion failed)",
-          13
-        ],
-        [
-          "Timeout",
-          6
-        ],
         [
           "ReferenceError (undefined symbol)",
-          1
+          4
         ],
         [
           "SyntaxError (parse/unsupported syntax)",
-          1
+          2
         ]
       ]
     }
   ],
   "top_failure_modes": [
-    [
-      "Test262Error (assertion failed)",
-      13
-    ],
-    [
-      "Timeout",
-      6
-    ],
     [
       "ReferenceError (undefined symbol)",
-      1
+      4
     ],
     [
       "SyntaxError (parse/unsupported syntax)",
-      1
+      2
     ]
   ],
   "pinned_commit": "d5e73fc8d2c663554fb72e2380a8c2bc1a318a33",
-  "elapsed_seconds": 224.9,
+  "elapsed_seconds": 42.1,
   "workers": 1
 }