Merge from upstream jdk/jdk12 up to tag jdk-12+26

[Aleksey Shipilev]

On 1/9/19 9:45 PM, Roman Kennke wrote:
> As $SUBJECT says. Brings our new sh/jdk12 to latest jdk12 tag and
> actually merges in Shenandoah ;-)
> 
> http://cr.openjdk.java.net/~rkennke/upstream-jdk12-merge-2019-01-09/outgoing.txt

Looks good!

-Aleksey