[FIX] dev:di:info duplicates plugin info

Author: coderimus

app/code/Magento/Developer/Model/Di/PluginList.php

@@ -143,9 +143,8 @@ private function addPluginToList($pluginInstance, $pluginMethod, $methodTypes, $
     {
         if ($methodTypes & $typeCode) {
             if (!array_key_exists($pluginInstance, $this->pluginList[$this->pluginTypeMapping[$typeCode]])) {
-                $this->pluginList[$this->pluginTypeMapping[$typeCode]][$pluginInstance] = [];
+                $this->pluginList[$this->pluginTypeMapping[$typeCode]][$pluginInstance][] = $pluginMethod;
             }
-            $this->pluginList[$this->pluginTypeMapping[$typeCode]][$pluginInstance][] = $pluginMethod ;
         }
     }
 }