[lworld] RFR: 8370880: [lworld] Split ciObjArrayKlass into ciRefArrayKlass and ciFlatArrayKlass [v4]

[Quan Anh Mai]

> Hi,
> 
> This PR splits `ciObjArrayKlass` into `ciRefArrayKlass` and `ciFlatArrayKlass`, aligns the hierarchy with the corresponding types of the VM.
> 
> Please kindly review, thanks a lot.

Quan Anh Mai has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits:

 - Remove unnecessary UseCompressedOops checks
 - Merge branch 'lworld' into ciRefArray
 - wrong value is passed as flat
 - remove redundant changes
 - Merge branch 'lworld' into ciRefArray
 - Revert "can only infer klass if exact"
   
   This reverts commit be6143624d30c9ebfa560dd8161aa70270c68d24.
 - can only infer klass if exact
 - Refactor ciObjArrayKlass to align with the VM type

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Changes: https://git.openjdk.org/valhalla/pull/1739/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1739&range=03
  Stats: 316 lines in 15 files changed: 110 ins; 146 del; 60 mod
  Patch: https://git.openjdk.org/valhalla/pull/1739.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1739/head:pull/1739

PR: https://git.openjdk.org/valhalla/pull/1739