improved SSLSession to-java unwrapping -> allow provider class

... here mostly since we're not really exposing that much

Author: kares

src/main/java/org/jruby/ext/openssl/SSLSession.java

@@ -170,8 +170,8 @@ public IRubyObject set_timeout(final ThreadContext context, IRubyObject timeout)
 
     @Override
     public Object toJava(Class target) {
-        if ( javax.net.ssl.SSLSession.class.isAssignableFrom(target) ) {
-            return sslSession();
+        if ( javax.net.ssl.SSLSession.class == target || target.isInstance(sslSession) ) {
+            return sslSession;
         }
         return super.toJava(target);
     }