RFR: 8373086: Make isexceeded001.java more robust

Thu Dec 4 09:38:10 UTC 2025

The original intended fix is to increase initial-heap-size so avoid gc, captured in [JDK-8373022](https://bugs.openjdk.org/browse/JDK-8373022). This is an alternative, which makes the test more resilient to changes in heaps/gcs.

Running `vmTestbase/nsk/monitoring/MemoryPoolMBean/isUsageThresholdExceeded/isexceeded002/TestDescription.java`
with `-XX:+UseParallelGC -Xcomp -XX:-TieredCompilation -XX:InitialRAMPercentage=0` fails about 10% of the time.

After applying the fix, `isexceeded002` passes 2,000 runs.

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Commit messages:
 - test-bug-nsk

Changes: https://git.openjdk.org/jdk/pull/28655/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28655&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8373086
  Stats: 8 lines in 2 files changed: 1 ins; 6 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28655.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28655/head:pull/28655

PR: https://git.openjdk.org/jdk/pull/28655