Merge branch '4.2'

* 4.2:
  [Phpunit] fixed support for PHP 5.3
  Response prepare method update
  [Workflow] Added missing license header
  Fix case when multiple loaders are providing paths for the same namespace
  Check if Client exists when test.client does not exist, to provide clearer exception message
  throw TypeErrors to prepare for type hints in 5.0
  [Form] Preventing validation of children if parent with Valid constraint has no validation groups
  [Form] Added ResetInterface to CachingFactoryDecorator
  Remove deprecated usage
  [Tests] fixed compatbility of assertEquals(): void
  Fixed usage of TranslatorInterface in form extension (fixes #30591)
  [Intl][4.2] Fix test
  [Intl] Fix test
  [Validator] Add the missing translations for the Arabic (ar) locale
  [Intl] Add compile binary
  Fix DebugCommand when chain loader is involved
  [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>