8205641: Make java/nio/channels/Selector/RacyDeregister.java noisier and flush after prints

[Alan Bateman]

On 26/06/2018 00:26, Brian Burkhalter wrote:
> https://bugs.openjdk.java.net/browse/JDK-8205641
> http://cr.openjdk.java.net/~bpb/8205641/webrev.00/
>
> Please review this small sub-task patch to make some changes to the test which will hopefully facilitate diagnosing the timeouts observed.
>
This looks okay to me.

BTW: Looking through the trail of issues on this test then it may be 
worth just re-writing to avoid the spinning threads that seems to cause 
to take a long time on some Windows machines.

-Alan