The current implementation of isc_queue uses Michael-Scott lock-free queue that in turn uses hazard pointers. It was discovered that the way we use the isc_queue, such complicated mechanism isn't really needed, because most of the time, we either execute the work directly when on nmthread (in case of UDP) or schedule the work from the matching nmthreads.
Provide alternative implementation for the isc_queue based on locked ISC_LIST.
(cherry picked from commit 7ef829a9)
Closes #3171 (closed)