Some executors cannot handle tasks that have been wrapped into
`{Runnable,Callable}Wrapper` because they require certain subclass of
`{Callable,Runnable}` in order to work. We have a test that
effectively disables instrumentation for such executors.
This change makes sure that tasks that do not need to be
wrapped (which essentially means anything that is not lambda) still
get traced in such executors. One notable example of affected executor
type is `ScheduledThreadPoolExecutor`.
Nikolay Martynov