processorLOD does not handle zero local elements

Summary

processorLOD does not handle zero local elements. E.g. if processorLODs::faceBox is used to pre-filter patches and the local number of patch faces is zero there is a division by zero.

Steps to reproduce

Attached test case and code. processorLOD.tgz

What is the current bug behaviour?

Division by zero

Environment information

• OpenFOAM version : v2112