RFR: 8164804: sun/security/ssl/SSLSocketImpl/CloseSocket.java makes not reliable time assumption

[Fernando Guallini]

test sun/security/ssl/SSLSocketImpl/CloseSocket.java verifies the behavior when a server closes the socket connection during a handshake. The server was waiting a fixed 100ms before closing it, but there was no guarantee that the client started the handshake before or during that time frame 

With this changeset, the server is checking whether the client thread has initiated handshake, and retrying if needed after waiting a short time. In addition, the test is now reusing SSLSocketTemplate to simplify sockets configuration and client/server synchronization

-------------

Commit messages:
 - close socket after handshake started

Changes: https://git.openjdk.java.net/jdk/pull/3856/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=3856&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8164804
  Stats: 103 lines in 1 file changed: 39 ins; 50 del; 14 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3856.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3856/head:pull/3856

PR: https://git.openjdk.java.net/jdk/pull/3856