Merge branch '3.4' into 4.2

* 3.4:
  [Phpunit] fixed support for PHP 5.3
  Response prepare method update
  [Workflow] Added missing license header
  Check if Client exists when test.client does not exist, to provide clearer exception message
  [Form] Preventing validation of children if parent with Valid constraint has no validation groups
  [Tests] fixed compatbility of assertEquals(): void
  [Intl] Fix test
  [Validator] Add the missing translations for the Arabic (ar) locale
  [Intl] Add compile binary
  [Form] Fixed some phpdocs

Author: fabpot

Resources/translations/validators.ar.xlf

@@ -330,6 +330,10 @@
                 <source>This Business Identifier Code (BIC) is not associated with IBAN {{ iban }}.</source>
                 <target>رمز المعرّف نشاط تجاري (BIC) هذا لا يرتبط مع IBAN {{ iban }}.</target>
             </trans-unit>
+            <trans-unit id="86">
+                <source>This value should be valid JSON.</source>
+                <target>هذه القيمة يجب أن تكون صالحة ل JSON.</target>
+            </trans-unit>
         </body>
     </file>
 </xliff>