[lworld] RFR: 8283573: [lworld] Make Object an abstract class

[Frederic Parain]

8283573: [lworld] Make Object an abstract class

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Commit messages:
 - Merge remote-tracking branch 'upstream/lworld' into new_object
 - Update JVMCI tests
 - Code improvement
 - Merge remote-tracking branch 'upstream/lworld' into new_object
 - Undo new Object changes
 - Fix compilation failure due to class name conflict
 - Merge remote-tracking branch 'upstream/lworld' into new_object
 - Revert new Object() changes
 - Merge remote-tracking branch 'upstream/lworld' into new_object
 - Merge remote-tracking branch 'upstream/lworld' into new_object
 - ... and 7 more: https://git.openjdk.java.net/valhalla/compare/5d03db86...9db93b17

Changes: https://git.openjdk.java.net/valhalla/pull/602/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=602&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283573
  Stats: 140 lines in 22 files changed: 117 ins; 0 del; 23 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/602.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/602/head:pull/602

PR: https://git.openjdk.java.net/valhalla/pull/602