RFR: 8309462: [AIX] vmTestbase/nsk/jvmti/RunAgentThread/agentthr001/TestDescription.java crashing due to empty while loop

[Martin Doerr]

Test fix for test failing on AIX because of undefined behavior in current implementation.

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Commit messages:
 - Backport cf9e6353cc6fe9e57a7a9883813d09892e7e7621

Changes: https://git.openjdk.org/jdk21/pull/9/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21&pr=9&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8309462
  Stats: 5 lines in 1 file changed: 4 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21/pull/9.diff
  Fetch: git fetch https://git.openjdk.org/jdk21.git pull/9/head:pull/9

PR: https://git.openjdk.org/jdk21/pull/9