RFR: 8271870: G1: Add objArray splitting when scanning object with evacuation failure

[Thomas Schatzl]

Hi all,

  please review this change that makes the object iteration path for evacuation failed objects the same as the one for regular objects (and indeed make both use the same code).

This has been made possible with the refactoring of object array task queues.

At the same time this also covers [JDK-8271871](https://bugs.openjdk.org/browse/JDK-8271871).

Testing: tier1-5, some perf testing with no differences

Thanks,
  Thomas

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Commit messages:
 - 8271870

Changes: https://git.openjdk.org/jdk/pull/24222/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24222&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8271870
  Stats: 101 lines in 3 files changed: 46 ins; 32 del; 23 mod
  Patch: https://git.openjdk.org/jdk/pull/24222.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24222/head:pull/24222

PR: https://git.openjdk.org/jdk/pull/24222