Delete workaround for time zone related failing test

Problem/Motivation

Due to this failing test https://www.drupal.org/pift-ci-job/71326 we added a workaround in the MonitoringTestBase::setUp(), the workaround is marked with a:

// @todo Remove when this issue is fixed: https://www.drupal.org/node/2611082
    date_default_timezone_set('Australia/Sydney');

, so this has to be removed when this issue is fixed: #2611082: Inconsistent time zones in web tests

Proposed resolution

Remove the @todo and the workaround.

Remaining tasks

User interface changes

API changes

Data model changes