LibJS: Add JSON.stringify

Libraries/LibJS/Tests/JSON.stringify-order.js

@@ -0,0 +1,36 @@
+load("test-common.js");
+
+try {
+    assert(JSON.stringify.length === 3);
+
+    let o = {
+        key1: "key1",
+        key2: "key2",
+        key3: "key3",
+    };
+
+    Object.defineProperty(o, "defined", {
+        enumerable: true,
+        get() {
+            o.prop = "prop";
+            return "defined";
+        },
+    });
+
+    o.key4 = "key4";
+
+    o[2] = 2;
+    o[0] = 0;
+    o[1] = 1;
+
+    delete o.key1;
+    delete o.key3;
+
+    o.key1 = "key1";
+
+    assert(JSON.stringify(o) === '{"0":0,"1":1,"2":2,"key2":"key2","defined":"defined","key4":"key4","key1":"key1"}');
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}