RFR: Upstream merge jdk/jdk -> shenandoah/jdk 2018-08-19

[Aleksey Shipilev]

On 08/19/2018 04:43 PM, Roman Kennke wrote:
> http://cr.openjdk.java.net/~rkennke/upstream-merge-2018-08-19/outgoing.txt

Looks fine, except that non-PCH builds would be broken until we get this fix:
  https://bugs.openjdk.java.net/browse/JDK-8209647

This is not a blocker, though, we can cherry-pick that later.

Thanks,
-Aleksey