RFR: Update copyrights

[Roman Kennke]

Looks good to me. Thanks!

Roman

> Employed the hand-written script to update copyrights to a consistent form, based on historical
> (Mercurial) data. This touches only the files that exist in Shenandoah webrev. The copyright update
> Webrev is really large, because it includes entire file contents, so patch is easier to review:
>   http://cr.openjdk.java.net/~shade/shenandoah/update-copyrights.patch
> 
> Testing: tier1_gc_shenandoah
> 
> Thanks,
> -Aleksey
>