Merge branch '3.4' into 4.3

* 3.4:
  [Filesystem] [Serializer] fixes English grammar typo
  [Monolog Bridge] Fixed accessing static property as non static.
  Improve Symfony description
  [Validator] Add Japanese translation
  Remove some unused methods parameters
  Avoid empty \"If-Modified-Since\" header in validation request
  [Validator] ConstraintValidatorTestCase: add missing return value to mocked validate method calls

Dumper/XliffFileDumper.php

@@ -41,7 +41,7 @@ public function formatCatalogue(MessageCatalogue $messages, $domain, array $opti
             return $this->dumpXliff1($defaultLocale, $messages, $domain, $options);
         }
         if ('2.0' === $xliffVersion) {
-            return $this->dumpXliff2($defaultLocale, $messages, $domain, $options);
+            return $this->dumpXliff2($defaultLocale, $messages, $domain);
         }
 
         throw new InvalidArgumentException(sprintf('No support implemented for dumping XLIFF version "%s".', $xliffVersion));
@@ -129,7 +129,7 @@ private function dumpXliff1($defaultLocale, MessageCatalogue $messages, $domain,
         return $dom->saveXML();
     }
 
-    private function dumpXliff2($defaultLocale, MessageCatalogue $messages, $domain, array $options = [])
+    private function dumpXliff2($defaultLocale, MessageCatalogue $messages, $domain)
     {
         $dom = new \DOMDocument('1.0', 'utf-8');
         $dom->formatOutput = true;