fixed endless error loop in error handler

this happended when `stream` was set on the response but the stream resouce was invalid
either because it was already sent or became invalid for some other cases.

fixes #9046

framework/web/ErrorHandler.php

@@ -69,7 +69,12 @@ class ErrorHandler extends \yii\base\ErrorHandler
     {
         if (Yii::$app->has('response')) {
             $response = Yii::$app->getResponse();
+            // reset parameters of response to avoid interference with partially created response data
+            // in case the error occurred while sending the response.
             $response->isSent = false;
+            $response->stream = null;
+            $response->data = null;
+            $response->content = null;
         } else {
             $response = new Response();
         }