[jdk21u-dev] RFR: 8336942: Improve test coverage for class loading elements with annotations of different retentions

[Liam Miller-Cushon]

This change improves annotation processing test coverage, see [JDK-8336942](https://bugs.openjdk.org/browse/JDK-8336942). I resolved a trivial merge conflict with JDK-8323684, which added the `nameToAnnotation` map. The modified test passes.

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Commit messages:
 - 8336942: Improve test coverage for class loading elements with annotations of different retentions

Changes: https://git.openjdk.org/jdk21u-dev/pull/1037/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1037&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8336942
  Stats: 12 lines in 1 file changed: 12 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1037.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1037/head:pull/1037

PR: https://git.openjdk.org/jdk21u-dev/pull/1037