Add policy parameter to allow tuning

[Georgii Evtushenko]

Not all CUB algorithm follow the scheme of accepting tuning policy at dispatch layer. This prevents these algorithms from being tuned.

Dispatch layers to be modified

Beta Give feedback

1. Add SelectedPolicy to DispatchHistogram
2. Add SelectedPolicy to DispatchReduceByKey
3. Add SelectedPolicy to DeviceRleDispatch
4. Add SelectedPolicy to DispatchThreeWayPartitionIf