RFR 8164533: [TEST_BUG] sun/security/ssl/SSLSocketImpl/CloseSocket.java failed with "Error while cleaning up threads after test"

[Svetlana Nikandrova]

Hello,

please review this test bug fix. Test failed because of staled threads 
left after execution.
Added try-with-resources statements to make sure test closes it's 
resources. Also as test is overall quite old-fashioned I've done some 
refactoring (hope now it looks better).

JBS:
https://bugs.openjdk.java.net/browse/JDK-8164533
Webrev:
http://cr.openjdk.java.net/~snikandrova/8164533/webrev.00/ 
<http://cr.openjdk.java.net/%7Esnikandrova/8164533/webrev.00/>

Thank you,
Svetlana