8213210: Change ServerSocket(SocketImpl impl) constructor to protected access

[Brian Burkhalter]

https://bugs.openjdk.java.net/browse/JDK-8213210

Please see diff included below. CSR to follow.

Thanks,

Brian

--- a/src/java.base/share/classes/java/net/ServerSocket.java
+++ b/src/java.base/share/classes/java/net/ServerSocket.java
@@ -76,10 +76,13 @@
     private boolean oldImpl = false;
 
     /**
-     * Package-private constructor to create a ServerSocket associated with
-     * the given SocketImpl.
+     * Creates a server socket with a user-specified {@code SocketImpl}.
+     *
+     * @param      impl an instance of a SocketImpl the subclass
+     *             wishes to use on the ServerSocket.
+     * @since 12
      */
-    ServerSocket(SocketImpl impl) {
+    protected ServerSocket(SocketImpl impl) {
         this.impl = impl;
         impl.setServerSocket(this);
     }