Bug 9735: Unit tests for get_template_and_user (cookies handling)

Bug 9735: Unit tests for get_template_and_user (cookies handling)

Galen found a case where the cookies array was not built flat. I add a
unit test for that (check the cookie array is flat) and also test the
cookies output of get_template_and_user so we are sure the &language=
parameter is correctly handled.

Sponsored-by: Universidad Nacional de Cordoba
Signed-off-by: Julian Maurice <julian.maurice@biblibre.com>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
- Tests in t/db_dependent/Auth.t pass
- Tested in intranet, OPAC logged in, OPAC logged out
  * Adding a valid language code to the URL switches the language
    as expected
  * Adding an invalid language code causes no change

Nice feature!

Signed-off-by: Galen Charlton <gmc@esilibrary.com>