updated classmap to fix test break

framework/classes.php

@@ -34,7 +34,6 @@ return [
   'yii\base\InvalidConfigException' => YII_PATH . '/base/InvalidConfigException.php',
   'yii\base\InvalidParamException' => YII_PATH . '/base/InvalidParamException.php',
   'yii\base\InvalidRouteException' => YII_PATH . '/base/InvalidRouteException.php',
-  'yii\base\MailEvent' => YII_PATH . '/base/MailEvent.php',
   'yii\base\Model' => YII_PATH . '/base/Model.php',
   'yii\base\ModelEvent' => YII_PATH . '/base/ModelEvent.php',
   'yii\base\Module' => YII_PATH . '/base/Module.php',
@@ -192,6 +191,7 @@ return [
   'yii\log\Target' => YII_PATH . '/log/Target.php',
   'yii\mail\BaseMailer' => YII_PATH . '/mail/BaseMailer.php',
   'yii\mail\BaseMessage' => YII_PATH . '/mail/BaseMessage.php',
+  'yii\mail\MailEvent' => YII_PATH . '/mail/MailEvent.php',
   'yii\mail\MailerInterface' => YII_PATH . '/mail/MailerInterface.php',
   'yii\mail\MessageInterface' => YII_PATH . '/mail/MessageInterface.php',
   'yii\mutex\DbMutex' => YII_PATH . '/mutex/DbMutex.php',