Improve user error messages on panic

[inancgumus]

This comment suggested a way to use the mapping layer for terminal errors (panic, etc.). The idea is that we will bubble up errors to the mapping layer, where it can decide whether to panic or to return an error to Goja.

We worked on a POC for a solution here. We now want to find a way to improve user error messages when a panic occurs. This is discussed in detail here.

We can use this issue to talk more and find a better solution.

[ankur22]

Thanks for raising this. To get the discussion started, an option could be to ask k6 to create a new API (for example AbortWholeTestRun(reason string)) that we can call (this was suggested to us as an option a while back when wanting to abort the whole process). This could be useful for a few reasons:

1. Current k6ext.Panic doesn't allow k6 to cleanup anything they may want to do before aborting.
2. This would help us with a cleaner error message for the user.
3. No panics.