[GREENFOOT-770] Reset while running at slow speed takes a long time

Set the speed to minimum via the slider, then run a scenario. If you click Pause followed by Reset, the pause is instant, and the rest is instant. However, if you run the scenario then directly click reset, it takes a long time to reset (waiting for the frame end, I'd guess). It seems like we can probably fix the reset while running so that it does the equivalent of whatever makes pause-reset so fast in this circumstance.

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Issue metadata

• Issue type: Task
• Priority: Medium