Setting worker affinities on non-contiguous NUMA sockets

[hbdeshmukh]

Right now the WorkOrderContainer assumes that if the workers belong to k NUMA sockets, the NUMA sockets that they cover are 0, 1, ... k-1. This may not be true always. e.g if the user wants the worker threads to be pinned to sockets 1 and 2 on a 4-socket machine.

The fix involves changing the WorkOrderContainer class and providing a set of NUMA sockets instead of just a count of NUMA sockets covered by the workers.

Thanks @cramja for pointing to this issue.