[aarch64-port-dev ] RFR: 2020-06-18, Bulk integration of Shenandoah 8u to aarch64-port/jdk8u-shenandoah

[Aleksey Shipilev]

https://cr.openjdk.java.net/~shade/shenandoah/merges/aarch64-port-8u-20200618/webrev.01/

This is another integration of Shenandoah 8u from our shenandoah/jdk8 staging repository. It was
generated by plain pull from shenandoah/jdk8/hotspot repository and automatic merge.

It fixes a few critical issues discovered during 8u stabilization.

Changes:
  Shenandoah: missing SystemDictionary roots in ShenandoahHeapIterationRootScanner
  Shenandoah: add JFR roots to root processor after JFR integration
  [backport] 8247310: Shenandoah: pacer should not affect interrupt status
  [backport] 8247474: Shenandoah: Windows build warning after JDK-8247310
  [backport] 8247358: Shenandoah: reconsider free budget slice for marking
  [backport] 8247560: Shenandoah: heap iteration holds root locks all the time
  Added tag aarch64-shenandoah-jdk8u262-b06-shenandoah-merge-2020-06-18 for changeset e49e42485e22

Testing: hotspot_gc_shenandoah {fastdebug,release}; it was also tested in sh/jdk8 with a few nightlies

-- 
Thanks,
-Aleksey