Merge branch '2.7' into 2.8

* 2.7:
  [DI] use assertStringEqualsFile when possible
  [VarDumper] Adapt to php 7.2 changes
  [Form][TwigBridge] Don't render _method in form_rest() for a child form
  [Validator] Fix IbanValidator for ukrainian IBANs

Author: nicolas-grekas

Resources/views/Form/form_div_layout.html.twig

@@ -308,7 +308,7 @@
         {% endif %}
     {%- endfor %}
 
-    {% if not form.methodRendered %}
+    {% if not form.methodRendered and form.parent is null %}
         {%- do form.setMethodRendered() -%}
         {% set method = method|upper %}
         {%- if method in ["GET", "POST"] -%}