[task/session-tests] Correctly display message on session continue test failure

PHPBB3-9732

tests/session/continue_test.php

@@ -78,7 +78,7 @@ class phpbb_session_continue_test extends phpbb_database_test_case
 		$this->assertSqlResultEquals(
 			$expected_sessions,
 			$sql,
-			'Check if no new session was created'
+			$message
 		);
 
 		$session->check_cookies($this, $expected_cookies);