Forcing a Buck Converter IC to behave like a Boost Converter
Please let me know what's going on and what you think would happen if
I built it on the breadboard. Will the chip keep cycling? Will it
function as a boost converter? Will the chip fail?


Always use simulation models as they are intended to be used because in the real world, odd-ball uses of circuits will result in definitely different behaviour compared to when tried out in a simulator.
Logic tells you that as soon as the output transistor shorts its collector to ground, the whole internal supply rail for the chip is also shorted out. So, why does the simulation work? Answer: because it assumes that vital internal nodes remain connected to a valid supply rail.

If you built in on breadboard it will fail to work (not even a slight chance of it working).