Empty select with attribute name="foo[]" bug fix

If you have a select with attribute name="foo[]", and you submit your form, http_build_query returns empty string as a result. In this case you get a form extra field validation error, because your field "foo" converts to
'' => bool(false)
issue #10808 crawler test
Merge branch '2.3' into 2.4

* 2.3:
  Minor doc fix.
  Simplified the way to update PHPUnit to the latest version
  [Process] Minor README update
  [HttpFoundation] Basic auth in url is broken when using PHP CGI/FPM
  Fixed a html error "Element ul is not closed" in logger.html.twig
  [HttpFoundation] Officialize the 308 redirect RFC
  issue #10808 crawler test
  Empty select with attribute name="foo[]" bug fix
  Fixed contextually wrong translation