RFR: 8240692: Cleanup of the javafx property objects

[Kevin Rushforth]

On Fri, 6 Mar 2020 22:43:50 GMT, Nir Lisker <nlisker at openjdk.org> wrote:

> A simple readability cleanup for the files that were changed in #113.
> 
> Note that the boolean property has an `instanceof` check that doesn't exist in the other properties.

I note that this also changes the wrapper property objects from anonymous subclasses of XxxxxPropertyBase to SimpleXxxxxProperty. This is more than just a readability cleanup. It's probably fine for this case, but that's why I want a second reviewer.

-------------

PR: https://git.openjdk.java.net/jfx/pull/141