<i18n dev> RFR: 8363925: Remove unused sun.nio.cs.ArrayEncoder::encode

[Volkan Yazici]

[JDK-6636319] introduced `ArrayEncoder`, composed of _only_ `encode` method. Later on [JDK-8054307] (JEP 254: Compact Strings)  removed all its usages. This method can safely be removed, hence this PR. Confirmed that `tier1-2` tests are clear on several platforms after changes.

[JDK-6636319]: https://bugs.openjdk.org/browse/JDK-6636319
[JDK-8054307]: https://bugs.openjdk.org/browse/JDK-8054307

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Commit messages:
 - Remove unused `sun.nio.cs.ArrayEncoder::encode`

Changes: https://git.openjdk.org/jdk/pull/27999/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27999&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8363925
  Stats: 261 lines in 6 files changed: 64 ins; 179 del; 18 mod
  Patch: https://git.openjdk.org/jdk/pull/27999.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27999/head:pull/27999

PR: https://git.openjdk.org/jdk/pull/27999