RFR: 8287805: Shenandoah: consolidate evacuate-update-root closures [v5]

[Zhengyu Gu]

> ShenandoahEvacuateUpdateMetadataClosure and ShenandoahEvacuateUpdateRootsClosure are mostly same, can be consolidated.
> 
> Also, only uses of ShenandoahEvacuateUpdateMetadataClosure all pass MO_UNORDERED template parameter, so it can be eliminated.
> 
> Test:
> 
> - [x] hotspot_gc_shenandoah

Zhengyu Gu has updated the pull request incrementally with one additional commit since the last revision:

  Aleksey's comment

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Changes:
  - all: https://git.openjdk.org/jdk/pull/9023/files
  - new: https://git.openjdk.org/jdk/pull/9023/files/f076e810..44f50839

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=9023&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=9023&range=03-04

  Stats: 7 lines in 1 file changed: 3 ins; 3 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9023.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9023/head:pull/9023

PR: https://git.openjdk.org/jdk/pull/9023