[8u] Review request: RT-36838 - Strange behavior of TreeItem's disclosure arrow // expanded/collapsed state not reflected correctly

[David Grieve]

Jonathan,
The issue with this one is that a call to reapply CSS is happening in 
the middle of the node being CSS updated.
I've attached a patch to https://javafx-jira.kenai.com/browse/RT-36838 
that defers the CSS reapply if the node's cssFlag is either update or 
reapply.