checkMesh -writeAllFields does not handle faceZones with boundary faces in them

Summary

checkMesh -writeAllFields does not handle faceZones with boundary faces in them. It fills a surfaceScalarField without checking if the faceZone does not contain any boundary faces.

Steps to reproduce

Use topoSet or setSet to put some boundary faces in a faceZone. In setSet on e.g. the lid-driven cavity tutorial:

faceSet f0 new labelToFace  (0 100 200 300 400 800 1000 1639)
faceZoneSet f0Zone new setToFaceZone f0

Environment information

• OpenFOAM version : develop