[jdk26u] RFR: 8373623: Refactor Serialization tests for Records to JUnit

[Shivangi Gupta]

Straight Backport. All tests passed.

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Commit messages:
 - Backport 1e357e9e976bfb0abc9d4e14bfb1572693622af8

Changes: https://git.openjdk.org/jdk26u/pull/67/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk26u&pr=67&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373623
  Stats: 431 lines in 20 files changed: 131 ins; 64 del; 236 mod
  Patch: https://git.openjdk.org/jdk26u/pull/67.diff
  Fetch: git fetch https://git.openjdk.org/jdk26u.git pull/67/head:pull/67

PR: https://git.openjdk.org/jdk26u/pull/67