Issue #1790 - SSL 100% CPU for HTTP/2.

DecryptedEndPoint.isInputShutdown() now also testing the raw EndPoint
for input shutdown, not only the SSLEngine.

jetty-io/src/main/java/org/eclipse/jetty/io/ssl/SslConnection.java

@@ -1121,7 +1121,7 @@ public class SslConnection extends AbstractConnection
         @Override
         public boolean isInputShutdown()
         {
-            return _sslEngine.isInboundDone();
+            return getEndPoint().isInputShutdown() || _sslEngine.isInboundDone();
         }
 
         private void notifyHandshakeSucceeded(SSLEngine sslEngine)