hg: jdk/sandbox: pre_shared_key extensio code cleanup, and a test update

[xuelei.fan at oracle.com]

Changeset: 2a820e434f17
Author:    xuelei
Date:      2018-06-03 19:43 -0700
URL:       http://hg.openjdk.java.net/jdk/sandbox/rev/2a820e434f17

pre_shared_key extensio code cleanup, and a test update

! src/java.base/share/classes/sun/security/ssl/PreSharedKeyExtension.java
! test/jdk/sun/security/ssl/SSLSocketImpl/AsyncSSLSocketClose.java