js-on-sx: Object(value) wraps primitives in their wrapper class

Per ES spec, Object('s') instanceof String, Object(42).constructor
=== Number, etc. Was passing primitives through as-is. Added cond
clauses to Object.__callable__ that dispatch by type and call
(js-new-call String/Number/Boolean (list arg)). The wrapper
constructors already store __js_*_value__ on this.
built-ins/Object: 16/50 → 26/50. conformance.sh: 148/148.

lib/js/test262-scoreboard.json

@@ -1,22 +1,22 @@
 {
   "totals": {
-    "pass": 78,
-    "fail": 15,
+    "pass": 77,
+    "fail": 16,
     "skip": 1,
     "timeout": 6,
     "total": 100,
     "runnable": 99,
-    "pass_rate": 78.8
+    "pass_rate": 77.8
   },
   "categories": [
     {
       "category": "built-ins/String",
       "total": 100,
-      "pass": 78,
-      "fail": 15,
+      "pass": 77,
+      "fail": 16,
       "skip": 1,
       "timeout": 6,
-      "pass_rate": 78.8,
+      "pass_rate": 77.8,
       "top_failures": [
         [
           "Test262Error (assertion failed)",
@@ -33,6 +33,10 @@
         [
           "SyntaxError (parse/unsupported syntax)",
           1
+        ],
+        [
+          "runner-error: sx_server closed stdout mid-epoch",
+          1
         ]
       ]
     }
@@ -53,9 +57,13 @@
     [
       "SyntaxError (parse/unsupported syntax)",
       1
+    ],
+    [
+      "runner-error: sx_server closed stdout mid-epoch",
+      1
     ]
   ],
   "pinned_commit": "d5e73fc8d2c663554fb72e2380a8c2bc1a318a33",
-  "elapsed_seconds": 158.2,
+  "elapsed_seconds": 238.6,
   "workers": 1
 }