fix(test): restore BackupServerTest to original intent with members and sleep

Keep backupMembers configured so initServer() actually starts the server,
preserving the test's original purpose of verifying start+close lifecycle.
Thread.sleep(1000) ensures channel is assigned before @after tearDown()
calls close(), avoiding the race. BackupServer.java is already reverted to
develop original so no production code is changed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: Little-Peony

framework/src/test/java/org/tron/common/backup/BackupServerTest.java

@@ -1,5 +1,7 @@
 package org.tron.common.backup;
 
+import java.util.ArrayList;
+import java.util.List;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
@@ -27,6 +29,9 @@ public void setUp() throws Exception {
     Args.setParam(new String[]{"-d", temporaryFolder.newFolder().toString()},
         TestConstants.TEST_CONF);
     CommonParameter.getInstance().setBackupPort(PublicMethod.chooseRandomPort());
+    List<String> members = new ArrayList<>();
+    members.add("127.0.0.2");
+    CommonParameter.getInstance().setBackupMembers(members);
     BackupManager backupManager = new BackupManager();
     backupManager.init();
     backupServer = new BackupServer(backupManager);
@@ -38,9 +43,10 @@ public void tearDown() {
     Args.clearParam();
   }
 
-  @Test
-  public void test() {
-    // backupMembers is empty so initServer() is a no-op; verify close() is safe
+  @Test(timeout = 60_000)
+  public void test() throws InterruptedException {
     backupServer.initServer();
+    // wait for the server to start so channel is assigned before close() is called
+    Thread.sleep(1000);
   }
 }