<i18n dev> RFR: 8308046: Move Solaris related Japanese charsets from java.base to jdk.charsets module

[Ichiroh Takiguchi]

According to "JDK 20 Internationalization Guide"
https://docs.oracle.com/en/java/javase/20/intl/supported-encodings.html
Following Solaris related Japanese charsets are in "contained in jdk.charsets module" list.

- PCK (x-PCK)
- EUC_JP_Solaris (x-eucJP-Open)

These are not supported by Linux platform, so they should not be in java.base module.

Note:
GHA Linux x86 builds were failed.
I think it's not related by my modified code.
I opened [JDK-8308051](https://bugs.openjdk.org/browse/JDK-8308051) GHA: Linux x86 builds failure

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Commit messages:
 - 8308046: [Linux] Move Solaris related Japanese charsets from java.base to jdk.charsets module

Changes: https://git.openjdk.org/jdk/pull/13973/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=13973&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8308046
  Stats: 14 lines in 3 files changed: 6 ins; 4 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/13973.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/13973/head:pull/13973

PR: https://git.openjdk.org/jdk/pull/13973