RFR: 8171405: java/net/URLConnection/ResendPostBody.java failed with "Error while cleaning up threads after test"

[Julia Boes]

Hi,

This fix involves a test that failed during thread cleanup. To address 
this, the ServerSocket is now being closed at the end and the server 
thread is joined. While at it, I removed some unnecessary whitespace.

webrev: http://cr.openjdk.java.net/~dfuchs/jboes/8171405/webrev.02/

bug report: https://bugs.openjdk.java.net/browse/JDK-8171405

Cheers,

Julia