JDK-8353955 changed the nsk/jdi tests so by default they are now run with includevirtualthreads=n, meaning vm.allThreads() won't return virtual threads. Any test that still required includevirtualthreads=y was modified to explicitly pass this argument.

There are a number of tests that still rely on vm.allThreads(), but pass even without includevirtualthreads=y. The reason is because they do no look for any specific debuggee threads in the list returned, but instead just perform the testing on the returned list. For example, the test might just verify that suspend counts are accurate for all threads in the list, but if a thread is missing, the test wouldn't notice.

It would be best if these tests were run with includevirtualthreads=y so they do a better job of testing virtual threads. I believe there are about 30 such tests.