RFR: 8366475: Rename MetaspaceShared class to AOTMetaspace [v2]

[Ioi Lam]

> Rename this class to with a naming convention that's consistent with other new AOT classes such as AOTClassLinker.
> 
> All changes are mechanical text replacement. Headers are resorted alphabetically.

Ioi Lam has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains three additional commits since the last revision:

 - Redo changes in comments and tests
 - Merge branch '8366474-rename_metaspaceobj_is_shared_to_in_aot_cache' into 8366475-rename-metaspace-shared-to-aot-metaspace
 - Rename MetaspaceShared -> AOTMetaspace

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Changes:
  - all: https://git.openjdk.org/jdk/pull/27017/files
  - new: https://git.openjdk.org/jdk/pull/27017/files/fc63ba0b..0a425935

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27017&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27017&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/27017.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27017/head:pull/27017

PR: https://git.openjdk.org/jdk/pull/27017