Fix up event dispatch to the new order.

src/MigrateBatchExecutable.php

@@ -167,7 +167,7 @@ public function finishBatch($success, $results, $ops, $interval) {
    */
   public function teardownMigration() {
     $this->getQueue()->deleteQueue();
-    $this->getEventDispatcher()->dispatch(MigrateEvents::POST_IMPORT, new MigrateImportEvent($this->migration, $this->message));
+    $this->getEventDispatcher()->dispatch(new MigrateImportEvent($this->migration, $this->message), MigrateEvents::POST_IMPORT);
     $this->migration->setStatus(MigrationInterface::STATUS_IDLE);
   }
 
@@ -191,7 +191,7 @@ protected function enqueue() {
         ]), 'error');
       return MigrationInterface::RESULT_FAILED;
     }
-    $this->getEventDispatcher()->dispatch(MigrateEvents::PRE_IMPORT, new MigrateImportEvent($this->migration, $this->message));
+    $this->getEventDispatcher()->dispatch(new MigrateImportEvent($this->migration, $this->message), MigrateEvents::PRE_IMPORT);
 
     // Knock off migration if the requirements haven't been met.
     try {
@@ -276,11 +276,11 @@ protected function processRowFromQueue(Row $row) {
     if ($save) {
       try {
         $destination = $this->migration->getDestinationPlugin();
-        $this->getEventDispatcher()->dispatch(MigrateEvents::PRE_ROW_SAVE, new MigratePreRowSaveEvent($this->migration, $this->message, $row));
+        $this->getEventDispatcher()->dispatch(new MigratePreRowSaveEvent($this->migration, $this->message, $row), MigrateEvents::PRE_ROW_SAVE);
         $destination_ids = $id_map->lookupDestinationIds($this->sourceIdValues);
         $destination_id_values = $destination_ids ? reset($destination_ids) : [];
         $destination_id_values = $destination->import($row, $destination_id_values);
-        $this->getEventDispatcher()->dispatch(MigrateEvents::POST_ROW_SAVE, new MigratePostRowSaveEvent($this->migration, $this->message, $row, $destination_id_values));
+        $this->getEventDispatcher()->dispatch(new MigratePostRowSaveEvent($this->migration, $this->message, $row, $destination_id_values), MigrateEvents::POST_ROW_SAVE);
         if ($destination_id_values) {
           // We do not save an idMap entry for config.
           if ($destination_id_values !== TRUE) {