[jdk11u-dev] RFR: 8301401: Allow additional characters for GB18030-2022 support

[Naoto Sato]

This is a backport of GB18030 Level 1 part of the JSR384 MR2 (https://jcp.org/aboutJava/communityprocess/mrel/jsr384/index2.html) Reference Implementation

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Commit messages:
 - 8301401: Allow additional characters for GB18030-2022 support

Changes: https://git.openjdk.org/jdk11u-dev/pull/1876/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk11u-dev&pr=1876&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8301401
  Stats: 102 lines in 8 files changed: 54 ins; 2 del; 46 mod
  Patch: https://git.openjdk.org/jdk11u-dev/pull/1876.diff
  Fetch: git fetch https://git.openjdk.org/jdk11u-dev.git pull/1876/head:pull/1876

PR: https://git.openjdk.org/jdk11u-dev/pull/1876