[jdk8u-dev] RFR: 8301400: Allow additional characters for GB18030-2022 support

[Naoto Sato]

This is a backport of GB18030 Level 1 part of the JSR337 MR5 (https://jcp.org/aboutJava/communityprocess/mrel/jsr337/index5.html) Reference Implementation

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Commit messages:
 - 8301400: Allow additional characters for GB18030-2022 support

Changes: https://git.openjdk.org/jdk8u-dev/pull/314/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk8u-dev&pr=314&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301400
  Stats: 86 lines in 5 files changed: 23 ins; 10 del; 53 mod
  Patch: https://git.openjdk.org/jdk8u-dev/pull/314.diff
  Fetch: git fetch https://git.openjdk.org/jdk8u-dev.git pull/314/head:pull/314

PR: https://git.openjdk.org/jdk8u-dev/pull/314