RFR: 8366475: Rename MetaspaceShared class to AOTMetaspace [v3]

[Ioi Lam]

> This PR is one (of many) steps in [JDK-8366473](https://bugs.openjdk.org/browse/JDK-8366473) (Refactor CDS source code with new AOT terminology):
> 
> 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 incrementally with one additional commit since the last revision:

  removed unnecessary includes

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27017/files
  - new: https://git.openjdk.org/jdk/pull/27017/files/0a425935..0cadae43

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27017&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27017&range=01-02

  Stats: 2 lines in 2 files changed: 0 ins; 2 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