As noted in NETCONF-591 if we have a slightly different XMLOutputFactory in the picture anyxml serialization fails.

This can be readily observed by dropping woodstox-core as a test dependency in yang-data-codec-xml - it will escalate multiple errors, some of which are showing NETCONF-591 breakage with others being comparison errors.

The most notable issue is anyxml encoding, which seems to be hacky at best and could probably be fixed by not using a transformer.