docs: Migrated performance testing doc from preview microsite to main training section.

        </ul>

      </li>

    </ul>

    <ul>

      <li><a href="<?cs var:toroot ?>training/testing/performance.html"

      description="How to automate UI performance testing.">

            <span class="en">Testing Display Performance</span>

            </a></li>

    <ul>

  </li>

  <!-- End best Testing -->