Fixing ToggleGroup synchronization

[Jesper Skov]

Hi,

I happened to fall over this issue:

https://bugs.openjdk.java.net/browse/JDK-8198402

while reading another jfx PR.


I have a shot at a fix:

https://github.com/openjdk/jfx/compare/master...jskov:toggleGroupSync-JDK-8198402

But I was not entirely sure if just submitting a PR without saying hello
first was OK? :)


The OCA has been sent. Should I await some feedback from oracle-ca_us
before I submit the PR?

Cheers,
Jesper