JDK-8200206: Adding an animation to more than one parent results in inconsistent state

[Nir Lisker]

Hello,

Iv'e created bug https://bugs.openjdk.java.net/browse/JDK-8200206. The
behavior was noticed back when writing missing documentation for Transition
[1]. Please evaluate.

Thanks,
Nir

[1]
http://mail.openjdk.java.net/pipermail/openjfx-dev/2018-January/021249.html