MEDIUM: tasks: More code factorization

MEDIUM: tasks: More code factorization

There is some code that should run no matter if the task was killed or
not, and was needlessly duplicated, so only use one instance.
This also fixes a small bug when a tasklet that got killed before it
could run would still count as a tasklet that ran, when it should not,
which just means that we'd run one less useful task before going back to
the poller.
This commit is mostly cosmetic, and should not have any impact.