Merge branch '5.4' into 6.3

* 5.4:
  Fix support to denormalize plain object types
  [Routing] Restore aliases removal in RouteCollection::remove()
  remove duplicated service definition

Author: nicolas-grekas

Tests/Fixtures/xml/services14.xml

@@ -3,10 +3,6 @@
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd">
     <services>
-        <service id="monolog.logger" parent="monolog.logger_prototype">
-            <argument index="0">app</argument>
-        </service>
-
         <service id="logger" alias="monolog.logger" />
 
         <service id="monolog.logger" parent="monolog.logger_prototype">