N°2651 rollback gitignore for lib tests dirs

Too dangerous ! We'll work properly on this but for 2.8

lib/symfony/class-loader/Tests/Fixtures/Namespaced/WithFileMagic.php

@@ -0,0 +1,15 @@
+<?php
+
+/*
+ * foo
+ */
+
+namespace Namespaced;
+
+class WithFileMagic
+{
+    public function getFile()
+    {
+        return __FILE__;
+    }
+}