events: add initEvent to Event

Refs: https://dom.spec.whatwg.org/#dom-event-initevent

Author: deokjinkim

lib/internal/event_target.js

@@ -123,6 +123,23 @@ class Event {
     this[kIsBeingDispatched] = false;
   }
 
+  /**
+   * @param {string} type
+   * @param {boolean} [bubbles]
+   * @param {boolean} [cancelable]
+   */
+  initEvent(type, bubbles = false, cancelable = false) {
+    if (arguments.length === 0)
+      throw new ERR_MISSING_ARGS('type');
+
+    if (this[kIsBeingDispatched]) {
+      return;
+    }
+    this[kType] = `${type}`;
+    this.#bubbles = !!bubbles;
+    this.#cancelable = !!cancelable;
+  }
+
   [customInspectSymbol](depth, options) {
     if (!isEvent(this))
       throw new ERR_INVALID_THIS('Event');
@@ -307,6 +324,7 @@ ObjectDefineProperties(
       configurable: true,
       value: 'Event',
     },
+    initEvent: kEnumerableProperty,
     stopImmediatePropagation: kEnumerableProperty,
     preventDefault: kEnumerableProperty,
     target: kEnumerableProperty,

test/wpt/status/dom/events.json

@@ -8,14 +8,6 @@
       ]
     }
   },
-  "Event-constructors.any.js": {
-    "fail": {
-      "expected": [
-        "Untitled 2",
-        "Untitled 3"
-      ]
-    }
-  },
   "Event-dispatch-listener-order.window.js": {
     "skip": "document is not defined"
   },