Add a simple test for the z modifier
Add a simple test for the z modifier

Reviewed-by: Andy Polyakov <015edf36635e030d5e009e08808a59984e629740@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3064)
openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl,openssl/openssl