[jdk21u-dev] RFR: 8316559: Refactor some util/Calendar tests to JUnit

[Goetz Lindenmaier]

I backport this for parity with 21.0.4-oracle.

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Commit messages:
 - Backport 355811a996544c54cde9ff232450f5e5c8e1e632

Changes: https://git.openjdk.org/jdk21u-dev/pull/363/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=363&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8316559
  Stats: 813 lines in 10 files changed: 339 ins; 259 del; 215 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/363.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/363/head:pull/363

PR: https://git.openjdk.org/jdk21u-dev/pull/363