Remove terminally deprecated constructor in GSSUtil

Summary

The constructor of GSSUtil was terminally deprecated and should be removed.

Problem

Default constructor accidentally included in a class.

Solution

Remove the terminally deprecated constructor by making it private.

Specification

--- a/src/jdk.security.jgss/share/classes/com/sun/security/jgss/GSSUtil.java
+++ b/src/jdk.security.jgss/share/classes/com/sun/security/jgss/GSSUtil.java
@@ -37,8 +37,7 @@ public class GSSUtil {
     /**
      * Do not call.
      */
-    @Deprecated(since="16", forRemoval=true)
-    public GSSUtil() {}
+    private GSSUtil() {}

     /**
      * Use this method to convert a GSSName and GSSCredential into a