RFR: Merge jdk8u:master

[Andrew John Hughes]

Merge jdk8u382-b02

GHA builds will not work until [JDK-8293107](https://bugs.openjdk.org/browse/JDK-8293107) is merged in 8u462-b01

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Commit messages:
 - Merge jdk8u382-b02
 - 8307531: [aarch64] JDK8 single-step debugging is extremely slow
 - 8303028: Update system property for Java SE specification maintenance version
 - 8305681: Allow additional characters for GB18030-2022 (Level 2) support
 - 8301400: Allow additional characters for GB18030-2022 support

The merge commit only contains trivial merges, so no merge-specific webrevs have been generated.

Changes: https://git.openjdk.org/shenandoah-jdk8u/pull/48/files
  Stats: 135 lines in 10 files changed: 58 ins; 14 del; 63 mod
  Patch: https://git.openjdk.org/shenandoah-jdk8u/pull/48.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk8u.git pull/48/head:pull/48

PR: https://git.openjdk.org/shenandoah-jdk8u/pull/48