[jdk21u-dev] RFR: 8343124: Tests fails with java.lang.IllegalAccessException: class com.sun.javatest.regtest.agent.MainWrapper$MainTask cannot access

[Goetz Lindenmaier]

I backport this for parity with 21.0.8-oracle

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Commit messages:
 - Backport dafa2e55adb6b054c342d5e723e51087d771e6d6

Changes: https://git.openjdk.org/jdk21u-dev/pull/1666/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1666&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343124
  Stats: 264 lines in 2 files changed: 102 ins; 95 del; 67 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1666.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1666/head:pull/1666

PR: https://git.openjdk.org/jdk21u-dev/pull/1666