Add explicit cast to ArcanistUnitConsoleRenderer unit test

Summary:
D25848 was incomplete. `$seconds` itself is not an int but a float.
Thus explicitly also cast `$seconds` to int to avoid an error in PHP 8.1 and later.

Test Plan: Run `bin/arc unit --everything`

Reviewers: O1 Blessed Committers, valerio.bozzolan

Reviewed By: O1 Blessed Committers, valerio.bozzolan

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Tags: #arcanist

Differential Revision: https://we.phorge.it/D25856

src/unit/renderer/ArcanistUnitConsoleRenderer.php

@@ -83,7 +83,7 @@ final class ArcanistUnitConsoleRenderer extends ArcanistUnitRenderer {
   private function formatTime($seconds) {
     if ($seconds >= 60) {
       $minutes = (int)floor($seconds / 60);
-      return pht('%dm%02ds', $minutes, round($seconds % 60));
+      return pht('%dm%02ds', $minutes, round((int)$seconds % 60));
     }
 
     if ($seconds >= 1) {