SSL_get0_group_name
const char *SSL_get0_group_name(SSL *s);
if (!TEST_str_eq(group_name, SSL_get0_group_name(serverssl))
|| !TEST_str_eq(group_name, SSL_get0_group_name(clientssl)))
if (!TEST_str_eq(SSL_get0_group_name(serverssl), kexch_name0)
|| !TEST_str_eq(SSL_get0_group_name(clientssl), kexch_name0))