RFR: 8353955: nsk/jdi tests should be fixed to not always require includevirtualthreads=y

[Chris Plummer]

This is just a preliminary review. I'd like to get some approval for the approach I'm taking. There are over 300 tests that need to be fixed. I've just fixed a handful in this PR to give a feel for the changes I plan on making. If they look ok to you, then I'll update this PR with the needed changes to the rest of the tests.

What this PR is fixing is the issue with all of our nsk/jdi testing being done with includevirtualthreads=y even though debuggers typically use the default includevirtualthreads=n. As a result we have a testing gap with includevirtualthreads=n. There are nearly 1200 nsk/jdi tests. Only about 350 actually need includevirtualthreads=y. I plan making includevirtualthreads=n the default for nsk/jdi tests unless the test does something to override the default and request includevirtualthreads=y.

includevirtualthreads=y forces the debug agent to track all virtual threads so they are returned by vm.allThreads(). Some tests need this since they use vm.allThreads() to find the debuggee threads. Without includevirtualthreads=y, vm.allThreads() usually won't return any virtual threads (although it might return some for which events have been triggered).

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Commit messages:
 - get rid of commented out change
 - Don't always use includevirtualthreads=y

Changes: https://git.openjdk.org/jdk/pull/24606/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=24606&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8353955
  Stats: 36 lines in 18 files changed: 34 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/24606.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/24606/head:pull/24606

PR: https://git.openjdk.org/jdk/pull/24606