RFR: 8372809: Test vmTestbase/nsk/jdi/ThreadReference/isSuspended/issuspended001/TestDescription.java failed: JVMTI_ERROR_THREAD_NOT_ALIVE

[Chris Plummer]

Fix a couple of asserts that are now being triggered after the changes for [JDK-8282441](https://bugs.openjdk.org/browse/JDK-8282441) were introduced. I had already run into these asserts while working on [JDK-8371380](https://bugs.openjdk.org/browse/JDK-8371380), and had already fixed them there. However, [JDK-8371380](https://bugs.openjdk.org/browse/JDK-8371380) likely is not going to be pushed for JDK 26, so I have moved the fixes to this PR.

You can also find the fixes I moved over from [JDK-8282441](https://bugs.openjdk.org/browse/JDK-8282441) here: https://github.com/openjdk/jdk/pull/28485/files#diff-65eb4035b1d9bb5ceaab430461cd782069fe88c0a7d0438964c041caf0aa5eec

Tested by running failed test case a few hundred times, and also all tier5 CI svc tests, which includes a lot of JDI related testing with virtual threads enabled. Also ran tier1 CI.

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Commit messages:
 - Cleanup some assert issues

Changes: https://git.openjdk.org/jdk/pull/28587/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28587&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8372809
  Stats: 18 lines in 1 file changed: 11 ins; 1 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/28587.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28587/head:pull/28587

PR: https://git.openjdk.org/jdk/pull/28587