[jdk21u] RFR: 6928542: Chinese characters in RTF are not decoded

[Ichiroh Takiguchi]

6928542: Chinese characters in RTF are not decoded

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Commit messages:
 - Backport a26f7c03c72e4efe6d3219d294294c554aebc631

Changes: https://git.openjdk.org/jdk21u/pull/415/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=415&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-6928542
  Stats: 286 lines in 3 files changed: 282 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk21u/pull/415.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/415/head:pull/415

PR: https://git.openjdk.org/jdk21u/pull/415