[DependencyInjection] Roll back changes made to generated files.

Original change was made in e9022adaef.

src/Symfony/Component/DependencyInjection/Tests/Fixtures/php/services9_compiled.php

@@ -201,7 +201,7 @@ class ProjectServiceContainer extends Container
         $this->services['method_call1'] = $instance = new \FooClass();
 
         $instance->setBar($this->get('foo'));
-        $instance->setBar(null);
+        $instance->setBar(NULL);
 
         return $instance;
     }

src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/services1.yml

@@ -0,0 +1 @@
+

src/Symfony/Component/DependencyInjection/Tests/Fixtures/yaml/services8.yml

@@ -4,3 +4,4 @@ parameters:
     bar: 'foo is %%foo bar'
     escape: '@@escapeme'
     values: [true, false, null, 0, 1000.3, 'true', 'false', 'null']
+