Create per-thread task and memory context for zonemgr
Create per-thread task and memory context for zonemgr
Previously, the zonemgr created 1 task per 100 zones and 1 memory context per 1000 zones (with minimum 10 tasks and 2 memory contexts) to reduce the contention between threads.
Instead of reducing the contention by having many resources, create a per-nm_thread memory context, loadtask and zonetask and spread the zones between just per-thread resources.