[FEAT MERGE] Merge syslog user experience improvement to master

Co-authored-by: Charles0429 <xiezhenjiang@gmail.com>
Co-authored-by: tino247 <tino247@126.com>
Co-authored-by: chaser-ch <chaser.ch@antgroup.com>

src/observer/table_load/ob_table_load_merger.cpp

@@ -156,7 +156,7 @@ int ObTableLoadMerger::start()
 
 void ObTableLoadMerger::stop()
 {
-  LOG_WARN("LOAD MERGE STOP");
+  LOG_WARN_RET(OB_SUCCESS, "LOAD MERGE STOP");
   is_stop_ = true;
   // 停止table合并
   table_compact_ctx_.stop();