RFR: 8219197: ThreadGroup.enumerate() may return wrong value

[Pavel Rappo]

Using a bunch of Semaphores here seems a bit surprising. One more CountDownLatch
or CyclicBarrier *might* have been better. But I guess it's not of concern.

For the diagnostic purposes I would add a newline between

  t4.join(); t3.join();

since they throw exceptions. Otherwise looks good. Thanks for doing this.

-Pavel

> On 13 Mar 2019, at 14:41, Pavel Rappo <pavel.rappo at oracle.com> wrote:
> 
> I'm reading the test. Still trying to figure out how it works in detail. Give me
> some more time to get comfortable with it and I will reply to the list. At the
> very least I would (suggestion) change the @summary. After all if this group is
> being destroyed, and this is the only call, then 0 would be a correct value,
> wouldn't it?
> 
> -Pavel