[11] RFC: Pick up 11.0.8+3 to sh/jdk11

[Roman Kennke]

Ok, let's do it!

Thanks,
Roman


> Upstream published 11.0.8+3, let's pick those up to sh/jdk11.
> 
> Merge it trivial (only tags). I would tag the result shenandoah-jdk-11.0.8+3 immediately.
> 
> Testing: hotspot_gc_shenandoah {fastdebug,release}
>