RFR: 8359119: Change Charset to use StableValue [v2]

[Per Minborg]

> Fields and methods can better leverage the Stable Value API compared to using DCL and holder classes. There are also some fields that can be marked `@Stable`.
> 
> This PR passes tier1, tier2, and tier3 tests on multiple platforms.

Per Minborg has updated the pull request incrementally with three additional commits since the last revision:

 - Revert for loop
 - Revert more
 - Revert changes

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25727/files
  - new: https://git.openjdk.org/jdk/pull/25727/files/57edd190..21a43faa

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25727&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25727&range=00-01

  Stats: 21 lines in 1 file changed: 12 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk/pull/25727.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25727/head:pull/25727

PR: https://git.openjdk.org/jdk/pull/25727