Waiting on the queue in the `cleanup` function causes and infinite loop if an error occurred earlier.

[manon-traverse]

The cleanup function waits on the graphics queue as a just-in-case since that code can be called when an error occured. However in certain cases that just-in-case wait can cause the program to hang, preventing the error from being printed. As far as I can tell the issue happens if the error occurs in the process of submitting a command buffer.

I think we should also consider just leaking everything on an error (or maybe always?) because the OS and driver will clean-up after the user-space program terminates anyway.