TTL wait=0 bug

[kianzarrin]

TMPE.zip fixes #1497 see issue

Test

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created a setup like this video https://youtu.be/EqkzznhV6hc?t=760 result:

• prev code: step3 did not wait for pedestrians to pass
• fixed code: step3 properly waits for pedestrian to pass

side effects

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the fix is guarded by ChangeMetric != StepChangeMetric.NoWait so it has not effect on other change metrics.