VisIt requires ghost zones for XDMF data

[BenWibking]

VisIt does not correctly render contours when ghost zones are not provided for XDMF files. (However, this is not an issue for OpenPMD files, ADIOS2 files, and small number of other formats.)

For details, see: https://visit-sphinx-github-user-manual.readthedocs.io/en/v3.4.0/data_into_visit/AdvancedTopics.html#ghost-zones

[Yurlungur]

We have the ability to output ghost zones, but I don't remember whether or not that's threaded through the XDMF... I don't think it is.