JSS.Lib: Implement the object constructor as a singleton

The Object constructor in javascript is a global object. So we imitate
that behaviour as a singleton.

JSS.Lib/Execution/Realm.cs

@@ -90,8 +90,7 @@ private Dictionary<string, Property> CreateGlobalProperties()
         Dictionary<string, Property> globalProperties = new();
 
         // 20.1.1 The Object Constructor, https://tc39.es/ecma262/#sec-object-constructor
-        var objectConstructor = new ObjectConstructor();
-        globalProperties.Add("Object", new Property(objectConstructor, new(true, false, true)));
+        globalProperties.Add("Object", new Property(ObjectConstructor.The, new(true, false, true)));
 
         return globalProperties;
     }

JSS.Lib/Runtime/Object.constructor.cs

@@ -8,9 +8,10 @@ namespace JSS.Lib.Runtime;
 internal class ObjectConstructor : Object, ICallable, IConstructable
 {
     // FIXME: The Object constructor has a [[Prototype]] internal slot whose value is %Function.prototype%.
-    public ObjectConstructor() : base(null)
+    private ObjectConstructor() : base(null)
     {
         // The Object constructor has a "length" property whose value is 1𝔽.
+        // FIXME: We should probably have a method for internally defining properties
         DataProperties.Add("length", new Property(new Number(1), new Attributes(true, false, true)));
     }
 
@@ -38,4 +39,13 @@ public Completion Construct(VM vm, List argumentList)
         Debug.Assert(asObject.IsNormalCompletion());
         return asObject;
     }
+
+    static public ObjectConstructor The
+    {
+        get
+        {
+            return _constructor;
+        }
+    }
+    static readonly private ObjectConstructor _constructor = new();
 }