iritkatriel

Following recent work [https://bugs.python.org/issue45711], the interpreter's internal
representation of the active exception (sys.exc_info()) is no longer the (typ, val, tb)
triplet, but just the exception instance.

For backward compatibility, existing APIs reconstruct the triplet from the instance, so
for example ``sys.exc_info()`` returns the triplet ``(type(exc), exc, exc.__traceback__)``,
where ``exc`` is the active exception.

Removing the triplet representation entirely is not something we can realistically
do anytime soon. However, it is feasible to reach a state where the triplet need not