[Form] keep compat with older tests

Author: nicolas-grekas

Tests/AbstractLayoutTest.php

@@ -432,7 +432,7 @@ public function testHelp()
         $html = $this->renderHelp($view);
 
         $this->assertMatchesXpath($html,
-'/div
+'/*[self::div or self::p]
     [@id="name_help"]
     [@class="help-text"]
     [.="[trans]Help text test![/trans]"]