Remove getClass func from Registry as it was moved to Utils class

src/Monolog/Registry.php

@@ -131,14 +131,4 @@ public static function __callStatic($name, $arguments)
     {
         return self::getInstance($name);
     }
-
-    /**
-     * @internal
-     */
-    public function getClass($object)
-    {
-        $class = \get_class($object);
-
-        return 'c' === $class[0] && 0 === strpos($class, "class@anonymous\0") ? get_parent_class($class).'@anonymous' : $class;
-    }
 }