[aarch64-port-dev ] RFR/RFC: Shenandoah 8u integration 2021-06-23

[Aleksey Shipilev]

Hi,

I would like to integrate the regular update of Shenandoah 8u to our integration repository,
aarch64-port/jdk8u-shenandoah. It comes with a few bugfixes.

Webrev:
   https://cr.openjdk.java.net/~shade/shenandoah/merges/aarch64-port-8u-20210623/webrev.01/

As you can see, there are no shared changes, and everything is within Shenandoah code. There is no 
merge changeset, as shenandoah/jdk8 forest is clean downstream of integration repository. I am 
tagging the whole thing as aarch64-shenandoah-jdk8u302-b03-shenandoah-merge-2021-06-23.

Testing: hotspot_gc_shenandoah; I see no build/test failures in builds.shipilev.net CI

-- 
Thanks,
-Aleksey