Exception thrown for for explicitly stopped simulation sequences

This is caused by changes in Ide954c322f682ff7bc9cbc53e8b5130e0294c9ce due to the scheduledAt queue being emptied during the execution of a task, resulting in an attempt to remove from an empty queue.

A task should not be executed between the peek and remove calls in AbstractActionContext.handleStep() to ensure that the removed task is the one returned by earlier.