Doc change notification not sent when XWiki.saveDocument() is called

There are 4 APIs for saveDocument(). Two of them take an oldDoc. These 2 APIs do send notification. The other 2 don't take an oldDoc and don't send a notification.

I believe the reason for this is that the saveDocument that takes an oldDoc is flawed. I can't rationalize the fact that the API would need to be passed an old document (prior to modification). The modifications should rather be held INSIDE the XWikiDocument object itself. See XWIKI-1517.

I'm attaching a test case that proves it doesn't work.