RFR: Merge jdk18

[Jesper Wilhelmsson]

Forwardport JDK 18 -> JDK 19

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Commit messages:
 - Merge remote-tracking branch 'jdk18/master' into Merge_jdk18
 - 8280592: Small javadoc tweaks to foreign API

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

Changes: https://git.openjdk.java.net/jdk/pull/7232/files
  Stats: 91 lines in 12 files changed: 0 ins; 42 del; 49 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7232.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7232/head:pull/7232

PR: https://git.openjdk.java.net/jdk/pull/7232