Document split with binary properties too eager

OAK-2392 changed the split logic for documents and creates a split document as soon as a binary property is overwritten. This happens quite frequently in a default Oak setup with oak-lucene. Lucene files are stored in the repository and many of them are short lived because they are merged into bigger segments later. This means all documents for those files are split as soon as the file is deleted. The revision garbage collection does not get any benefit from this, because it will remove the files anyway. It is actually more expensive, because the GC also needs to collect the split documents.

The split logic should be updated to only create a split document with binary properties when the node still exists at the current head revision.