[aarch64-port-dev ] RFR: Bulk integration from Shenandoah

[Roman Kennke]

Disregard the webrev, and review those updated changesets/webrev instead:

Changeset:
http://cr.openjdk.java.net/~rkennke/bulk-integration-2020-03-06/changesets.01

Full webrev:
http://cr.openjdk.java.net/~rkennke/bulk-integration-2020-03-06/webrev.01/

I forgot to include a number of recent backports.

Thank you,
Roman

> This imports recent changes from shenandoah/jdk8 to the integration repo
> aarch64-port/jdk8-shenandoah. It's all smallish improvements, bug-fixes,
> cleanups, etc.
> 
> Changesets:
> http://cr.openjdk.java.net/~rkennke/bulk-integration-2020-03-06/changesets.txt
> 
> Full webrev:
> http://cr.openjdk.java.net/~rkennke/bulk-integration-2020-03-06/webrev.00/
> 
> Merge was almost trivial. Most changes in shared code actually revert
> Shenandoah-specific changes.
> 
> Testing: shenandoah/jdk8 has baked in our nightly CI runs for quite a
> while. I have run build and hotspot_gc_shenandoah locally after the
> merge for sanity-test
> 
> Can I get a review?
> 
> Thanks,
> Roman
>