RFR: 8346985: Convert test/jdk/com/sun/jdi/ClassUnloadEventTest.java to Class-File API

[Adam Sotona]

This patch converts the remaining test/jdk/com/sun/jdi/ClassUnloadEventTest.java from ASM to Class-File API.

Please review.

Thanks,
Adam

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Commit messages:
 - 8346985: Convert test/jdk/com/sun/jdi/ClassUnloadEventTest.java to Class-File API

Changes: https://git.openjdk.org/jdk/pull/22915/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22915&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8346985
  Stats: 20 lines in 1 file changed: 3 ins; 10 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/22915.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22915/head:pull/22915

PR: https://git.openjdk.org/jdk/pull/22915