LibJS: Reorganize tests into subfolders

Libraries/LibJS/Tests/operators/instanceof-basic.js

@@ -0,0 +1,28 @@
+load("test-common.js");
+
+try {
+    function Foo() {
+        this.x = 123;
+    }
+
+    var foo = new Foo();
+    assert(foo instanceof Foo);
+
+    function Base() {
+        this.is_base = true;
+    }
+
+    function Derived() {
+        this.is_derived = true;
+    }
+
+    Object.setPrototypeOf(Derived.prototype, Base.prototype);
+
+    var d = new Derived();
+    assert(d instanceof Derived);
+    assert(d instanceof Base);
+
+    console.log("PASS");
+} catch(e) {
+    console.log("FAIL: " + e);
+}