event: cancelBubble is a property

Event#cancelBubble is property (and not a function). Change
Event#cancelBubble to a property and add a test.

PR-URL: #33613
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

PR-URL: #34015
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

test/parallel/test-eventtarget.js

@@ -70,6 +70,24 @@ ok(EventTarget);
   const ev = new Event('foo', {}, {});
   strictEqual(ev.type, 'foo');
 }
+{
+const ev = new Event('foo');
+  strictEqual(ev.cancelBubble, false);
+  ev.cancelBubble = true;
+  strictEqual(ev.cancelBubble, true);
+}
+{
+  const ev = new Event('foo');
+  strictEqual(ev.cancelBubble, false);
+  ev.stopPropagation();
+  strictEqual(ev.cancelBubble, true);
+}
+{
+  const ev = new Event('foo');
+  strictEqual(ev.cancelBubble, false);
+  ev.cancelBubble = 'some-truthy-value';
+  strictEqual(ev.cancelBubble, true);
+}
 {
   const ev = new Event('foo', { cancelable: true });
   strictEqual(ev.type, 'foo');