Only exit on panic in custom tasks

[doinkythederp]

What's the motivation for this feature?

The current panic handler will exit the entire program on a panic. However, it may improve reliability to keep the program running if a sub-task panics.

Describe the solution you'd like

Unwind and run destructors on panic, then if it's the main/entrypoint task, exit

Describe the drawbacks, if any

We would have to figure out how to get unwinding working. Also continuing the program could cause some sort of invalid state if using incorrectly.

Describe the alternative solutions, if any

We could just delete the current task instead of unwinding. This would mean destructors aren't run and memory isn't deallocated. We would have to store a list of mutexes that are locked by the current task and poison them.

Additional context

I know PROS does some unwinding stuff related to C++ destructors, so it might be possible to hook into those APIs.