RFC: Pick up jdk-11.0.7+4 to sh/jdk11

[Roman Kennke]

ok, let's do it!

Thanks,
Roman


> Upstream published jdk-11.0.7+4, let's pick it up.
> 
> The merge is trivial. I would tag the result shenandoah-jdk-11.0.7+4 right away.
> 
> Changeset list:
>   https://cr.openjdk.java.net/~shade/shenandoah/merges/jdk11-11.0.7%2b4/changesets.txt
> 
> Testing: hotspot_gc_shenandoah {fastdebug,release}
>