RFR: 8358255: Factor out boilerplate code of EventHandler properties in Scene and Window

[Andy Goryachev]

On Sun, 1 Jun 2025 21:42:17 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

> `EventHandler` property implementations in `Scene` and `Window` use anonymous classes derived from `ObjectPropertyBase`. We can remove about 650 lines of boilerplate code by using a common property class instead.

I like it very much.  Also saves a few bytes.
It's a trivial change, one reviewer is probably enough, but two is always better.

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Marked as reviewed by angorya (Reviewer).

PR Review: https://git.openjdk.org/jfx/pull/1819#pullrequestreview-2893041303