executor: Lower the log level from info to debug for index merge reader (#42597) (#42838)

close #41949

Author: ti-chi-bot

executor/index_merge_reader.go

@@ -757,7 +757,7 @@ func handleWorkerPanic(ctx context.Context, finished <-chan struct{}, ch chan<-
 			defer close(ch)
 		}
 		if r == nil {
-			logutil.BgLogger().Info("worker finish without panic", zap.Any("worker", worker))
+			logutil.BgLogger().Debug("worker finish without panic", zap.Any("worker", worker))
 			return
 		}
 
@@ -1073,7 +1073,7 @@ func (w *indexMergeTableScanWorker) pickAndExecTask(ctx context.Context, task **
 func (w *indexMergeTableScanWorker) handleTableScanWorkerPanic(ctx context.Context, finished <-chan struct{}, task **lookupTableTask, worker string) func(r interface{}) {
 	return func(r interface{}) {
 		if r == nil {
-			logutil.BgLogger().Info("worker finish without panic", zap.Any("worker", worker))
+			logutil.BgLogger().Debug("worker finish without panic", zap.Any("worker", worker))
 			return
 		}