RFR: Merge jdk19

[Daniel D. Daugherty]

Merge jdk19 -> jdk20.

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Commit messages:
 - Merge
 - 8290625: Test jdk/javadoc/tool/CheckManPageOptions.java after manpage update
 - 8278274: Update nroff pages in JDK 19 before RC
 - 8287916: Address the inconsistency between the constant array and pool size
 - 8285407: Improve Xalan supports
 - 8282676: Improve subject handling
 - 8284370: Improve zlib usage
 - 8283190: Improve MIDI processing
 - 8281866: Enhance MethodHandle invocations
 - 8281859: Improve class compilation
 - ... and 3 more: https://git.openjdk.org/jdk/compare/b1817a30...aaca8b9d

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

Changes: https://git.openjdk.org/jdk/pull/9578/files
  Stats: 504 lines in 28 files changed: 428 ins; 16 del; 60 mod
  Patch: https://git.openjdk.org/jdk/pull/9578.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9578/head:pull/9578

PR: https://git.openjdk.org/jdk/pull/9578