<AWT Dev> 8133514: Update NervousText demo to use java.version System property

[Iris Clark]

Hi, Phil.

> http://cr.openjdk.java.net/~prr/8133514/
> https://bugs.openjdk.java.net/browse/JDK-8133514

I'm not a Reviewer, but as the person who requested this change, I think it looks fine.

Thanks for handling it so quickly.

Regards,
iris