SyncWorkers do not run the init task before the first regular task

When using a SyncWorker in Taskmaster, the init task is run after the first regular task.
```php
$taskmaster = new Taskmaster();
$taskmaster->addWorker(new SyncWorker());
$taskmaster->setDefaultInitTask(new InitTask());

$task = new InitValidateTask();
$taskmaster->runTask($task);
$taskmaster->wait();

$task->getResult(); //false
```