testXHTML: use the global validator to check static html files

Reduce duplicated code.

product/ERP5/tests/testXHTML.py

@@ -225,14 +225,6 @@ class TestXHTMLMixin(ERP5TypeTestCase):
       self.fail(message)
 
   def test_html_file(self):
-    path_list = os.environ.get('CGI_PATH',
-    '/usr/lib/cgi-bin:/usr/lib/cgi-bin/w3c-markup-validator').split(os.pathsep)
-    for path in path_list:
-      validator_path = os.path.join(path, 'check')
-      if os.path.exists(validator_path):
-        validator = W3Validator(validator_path, show_warnings)
-        break
-    if validator is not None:
     skins_tool = self.portal.portal_skins
     path_list = []
     for script_path, script in skins_tool.ZopeFind(