RFR: 8370368: Apply java.io.Serial annotations in java.security.jgss

[Sergey Bylokhov]

Please review the application of the `@Serial` annotation ([JDK-8202385](https://bugs.openjdk.org/browse/JDK-8202385)) to types in the java.security.jgss module to enable stricter compile-time checking of serialization-related declarations.

Example of a similar change https://github.com/openjdk/jdk/pull/24891.

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Commit messages:
 - 8370368: Apply java.io.Serial annotations in java.security.jgss

Changes: https://git.openjdk.org/jdk/pull/27925/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27925&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8370368
  Stats: 33 lines in 10 files changed: 25 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/27925.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27925/head:pull/27925

PR: https://git.openjdk.org/jdk/pull/27925