LibJS: Add "constructor" property to constructor prototypes

Libraries/LibJS/Tests/Object.prototype.constructor.js

@@ -0,0 +1,28 @@
+try {
+    assert(Array.prototype.constructor === Array)
+    assert(Boolean.prototype.constructor === Boolean)
+    assert(Date.prototype.constructor === Date)
+    assert(Error.prototype.constructor === Error)
+    assert(Function.prototype.constructor === Function)
+    assert(Number.prototype.constructor === Number)
+    assert(Object.prototype.constructor === Object)
+
+    o = {}
+    assert(o.constructor === Object)
+
+    o = new Object
+    assert(o.constructor === Object)
+
+    a = []
+    assert(a.constructor === Array)
+
+    a = new Array
+    assert(a.constructor === Array)
+
+    n = new Number(3)
+    assert(n.constructor === Number)
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}