Scripting: better per script memory tracking

[IamPete1]

This moves away from using the provided lua memory tracking and "manualy" tracking via our alloc function. This means we can track the total allocation per run rather than just the memory change. Just tracking the change masks issues because garbage collection can happen during a script run. This change also allows us to track per script memory.

This adds lots of AP_SCRIPTING_CHECKS defines to check the memory count matches the lua one. It turns out AP_SCRIPTING_CHECKS are always enabled....

I have not tested the checks still all pass for every combination of script errors and garbage collection. Also not tested the repl.

[IamPete1]

This is currently reporting that a script can use a negative amount of memory. There are lots of checks in this, so I wonder if we have a genuine issue.

On master we don't get per script memory, so there is no way to tell.

[IamPete1]

Excitingly it panics on real hardware but not in SITL. More testing needed.....

[IamPete1]

I worked out the issue, when a script is removed it still has some memory cost, this needs to be accounted for so the totals still match up. I guess it gets garbage collected at some later point.

This is also the issue with getting negative per script memory. The total is always correct, but the garbage collector collects from multiple scripts so we cannot assign the collected memory to the script that has just run.

[IamPete1]

There does not seem to be any nice way to do this. So, I think I will give up for now. Moving to thread per script would be the solution, although would cost more memory overall.