TEST_BUG: closed/java/nio/channels/ReadOnlyBuffers.java doesn't clean-up

This test doesn't shutdown the UDP server so there is a thread running after the test ends.

"Thread-12" #97 daemon prio=5 os_prio=0 tid=0x25b3d800 nid=0x200c runnable [0x26ebf000]
   java.lang.Thread.State: RUNNABLE
at sun.nio.ch.DatagramChannelImpl.receive0(Native Method)
at sun.nio.ch.DatagramChannelImpl.receiveIntoNativeBuffer(DatagramChannelImpl.java:409)
at sun.nio.ch.DatagramChannelImpl.receive(DatagramChannelImpl.java:387)
at sun.nio.ch.DatagramChannelImpl.receive(DatagramChannelImpl.java:348)
- locked <0x0fb3ebb8> (a java.lang.Object)
at ReadOnlyBuffers$UdpEchoServer.run(ReadOnlyBuffers.java:98)
at java.lang.Thread.run(Thread.java:722)