[jdk21u-dev] RFR: 8317300: javac erroneously allows "final" in front of a record pattern

[Aleksey Shipilev]

Transplanted to jdk21u-dev from https://github.com/openjdk/jdk21u/pull/369

Clean backport to fix the new language feature support; innocuous, but fixing it earlier is beneficial for avoiding accidents (i.e. build failures when migrating to newer JDKs).

Additional testing:
 - [x] MacOS AArch64 server fastdebug, new test fails without the fix, passes with it
 - [x] MacOS AArch64 server fastdebug, `tools/javac` pass

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Commit messages:
 - Backport 5ca1beb30e35cc91bf170960fb832de6438de1de

Changes: https://git.openjdk.org/jdk21u-dev/pull/5/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=5&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8317300
  Stats: 30 lines in 3 files changed: 30 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/5.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/5/head:pull/5

PR: https://git.openjdk.org/jdk21u-dev/pull/5