RFR of JDK-8156505: output more information when java/nio/channels/AsynchronousSocketChannel/Basic.java fails

[Hamlin Li]

Would you please review below patch?

There are 2 kinds of failures reported by JDK-8156505 in test 
java/nio/channels/AsynchronousSocketChannel/Basic.java, both say that 
instead of expected exception some unknown exception is caught. need to 
add some debugging code to get the exact unknown exception.

bug: https://bugs.openjdk.java.net/browse/JDK-8169764
webrev: http://cr.openjdk.java.net/~mli/8169764/webrev.00/

Thank you

-Hamlin