8213235: java/nio/channels/SocketChannel/AsyncCloseChannel.java fails with threads that didn't exit

[Brian Burkhalter]

https://bugs.openjdk.java.net/browse/JDK-8213235
http://cr.openjdk.java.net/~bpb/8213235/webrev.00/

1) Remove @run tag with “othervm” requirement.
2) Make the threads created inside TargetServer::runEx() stop spinning when ‘keepGoing’ becomes ‘false.’

With only #1 above applied, the test appears always to fail in the CI test environment.
With #2 above also applied, the test passed more than two hundred iterations in the CI system.

Thanks,

Brian