the queue has been removed from the global taskqueue_queues list. This
removes the need for the draining queue hack.
- Allow taskqueue_run() to be called with the taskqueue mutex held. It
can still be called without the lock for API compatiblity. In that case
it will acquire the lock internally.
- Don't lock the individual queue mutex in taskqueue_find() until after the
strcmp as the global queues mutex is sufficient for the strcmp.
- Simplify taskqueue_thread_loop() now that it can hold the lock across
taskqueue_run().
Submitted by: bde (mostly)
bd83e879fd