[jdk21u-dev] RFR: 8312049: runtime/logging/ClassLoadUnloadTest can be improved

[Daniel Hu]

Backport of [JDK-8312049](https://bugs.openjdk.org/browse/JDK-8312049): improving ClassLoadUnloadTest. Original commit does not apply cleanly due to this [backport](https://bugs.openjdk.org/browse/JDK-8323123) that renames createJavaProcessBuilder to createLimitedTestJavaProcessBuilder. Additionally, the options "-Xlog:class+load+cause" "-Xlog:class+load+cause+native" were not added until a later [version](https://bugs.openjdk.org/browse/JDK-8193513), thus these cases are excluded.

Passes tier1 tests on Linux x86 and MacOS aarch64, and most importantly, the test itself.

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Commit messages:
 - Backport 4676b40f17dd18941f5883cb9b989ad639992a50

Changes: https://git.openjdk.org/jdk21u-dev/pull/909/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=909&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8312049
  Stats: 35 lines in 1 file changed: 2 ins; 7 del; 26 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/909.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/909/head:pull/909

PR: https://git.openjdk.org/jdk21u-dev/pull/909