RFR: 8235598: Shenandoah: Update copyrights

[Zhengyu Gu]

Looks good and trivial

Thanks,

-Zhengyu

On 12/10/19 12:39 PM, Roman Kennke wrote:
> We accumulated a lot of copyright headers that went out-of-sync with
> reality. Let's fix them.
> 
> Issue:
> https://bugs.openjdk.java.net/browse/JDK-8235598
> Webrev:
> http://cr.openjdk.java.net/~rkennke/JDK-8235598/webrev.00/
> 
> Testing: build, hotspot_gc_shenandoah
> 
> Ok?
>