[FEATURE] Add FakeEventDispatcher inspired by Laravel

[simonschaufi]

See https://laravel.com/docs/10.x/events#testing for inspiration source and https://github.com/laravel/framework/blob/10.x/src/Illuminate/Support/Testing/Fakes/EventFake.php for the original source code.

How to use:

use TYPO3\CMS\Core\EventDispatcher\ListenerProvider;

$fakeEventDispatcher = new FakeEventDispatcher(new ListenerProvider($this->getContainer()));

// $this->subject is an Extbase Controller
$this->subject->injectEventDispatcher($fakeEventDispatcher);

// run code which should dispatch an event (dispatch controller)

$fakeEventDispatcher->assertDispatched(MyEvent::class);