[jdk17u-dev] RFR: 8167252: Some of Charset.availableCharsets() does not contain itself

[Goetz Lindenmaier]

I backport this for parity with 17.0.17-oracle.
I needed to do a full rebuild to make the change take effect.

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Commit messages:
 - Backport 3eeb681a0de87baa12b6eac5966e7f707b76c8bf

Changes: https://git.openjdk.org/jdk17u-dev/pull/3635/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=3635&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8167252
  Stats: 37 lines in 4 files changed: 31 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/3635.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/3635/head:pull/3635

PR: https://git.openjdk.org/jdk17u-dev/pull/3635