[9] review request: 8134709: Cannot compile FXDnD with JDK 9: DropTargetContext::addNotify, removeNotify not found

[Kevin Rushforth]

[fixed cut-and-paste error in the URL of the webrev and added bug 
description to subject line]

Sergey & Alexander,

Please review the following, which will allow the FX sdk to build with 
JDK 9.

https://bugs.openjdk.java.net/browse/JDK-8134709
http://cr.openjdk.java.net/~kcr/8134709/webrev.00/

The premise of the fix, which just comments out the calls to the removed 
methods, is that since the existing FX / Swing Drag & Drop functionality 
has been broken for all users of JDK 9 ea for the last several months, 
we can live with it broken for a little while longer; I doubt any FX 
developer who is current testing it with JDK 8u as a boot JDK and their 
own build of FX will notice. I will file a follow-on JIRA to fix it 
after we move to JDK 9 as a boot JDK. I didn't think it was worth 
putting in reflection code for this case, but if you feel otherwise, 
then let me know.

-- Kevin