Nope, power is coming from wheels and car is slowing down. When it stops there is nothing left to power engine to pump air into turbo.
I know what is your point, the answer is that the whole "raised pressure" area is a closed system and produces more and more friction to keep high pressure - no excessive energy comes out. If you keep feeding energy to wheels though, at some point turbo will "leak" the excessive pressure to the exhaust and it won't raise infinitely in the inlet. So basically you turn cars kinetic energy to friction.
I'm not an expert in physics - I do know that it just works (usefull thing to learn here is that when your brakes fade, turn off your engine and push maximum throttle - engine will compress air and generate more friction which will stop the car)
I would also like to know more about this so it is a nice topic for offtopic/general racing talk - let us talk there and keep the topic here which is ALS for LFS