Fix test fails in MonitoringUITest

After #665790: Redesign the status report page got committed, the run cron messages were changed.

+++ b/core/modules/system/system.install
@@ -535,14 +535,20 @@ function system_requirements($phase) {
-        '#prefix' => '<br />',
-        '#markup' => t('To run cron from outside the site, go to <a href=":url">@cron</a>', [':url' => $cron_url, '@cron' => $cron_url]),
+        '#prefix' => '<span class="cron-description__run-cron">',
+        '#suffix' => '</span>',
+        '#type' => 'link',
+        '#title' => t('Run cron'),
+        '#url' => Url::fromRoute('system.run_cron'),

and

-        '#markup' => t('You can <a href=":cron">run cron manually</a>.', [':cron' => \Drupal::url('system.run_cron')]),
+        '#type' => 'link',
+        '#prefix' => '(',
+        '#title' => t('more information'),
+        '#suffix' => ')',
+        '#url' => Url::fromRoute('system.cron_settings'),

Changing assertions accordingly.