Avoid printing stack trace for ClosedChannelException in agent launch log (#10927)

Author: jglick

core/src/main/java/hudson/slaves/SlaveComputer.java

@@ -66,6 +66,7 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.PrintStream;
+import java.nio.channels.ClosedChannelException;
 import java.nio.charset.Charset;
 import java.security.Security;
 import java.util.ArrayList;
@@ -641,9 +642,11 @@ public void onClosed(Channel c, IOException cause) {
                 // Orderly shutdown will have null exception
                 if (cause != null) {
                     offlineCause = new ChannelTermination(cause);
-                    Functions.printStackTrace(cause, taskListener.error("Connection terminated"));
-                } else {
+                }
+                if (cause == null || cause instanceof ClosedChannelException) {
                     taskListener.getLogger().println("Connection terminated");
+                } else {
+                    Functions.printStackTrace(cause, taskListener.error("Connection terminated"));
                 }
                 closeChannel();
                 try {