Toolbar icons broken in languages other than English

Problem:

When I switch the interface language to German, the toolbar looks like this for me:

This is because the css class names icon-* on the menu links are being localized:

<li class="collapsed"><a href="/admin/structure" id="toolbar-link-admin-structure" class="icon icon-struktur">Struktur</a></li>
<li class="leaf"><a href="/admin/appearance" id="toolbar-link-admin-appearance" class="icon icon-design">Design</a></li>
<li class="leaf"><a href="/admin/people" id="toolbar-link-admin-people" class="icon icon-benutzer">Benutzer</a></li>
<li class="leaf"><a href="/admin/modules" id="toolbar-link-admin-modules" class="icon icon-extend">Extend</a></li>
<li class="collapsed"><a href="/admin/config" id="toolbar-link-admin-config" class="icon icon-konfiguration active">Konfiguration</a></li>
<li class="collapsed"><a href="/admin/reports" id="toolbar-link-admin-reports" class="icon icon-berichte">Berichte</a></li>
<li class="last leaf"><a href="/admin/help" id="toolbar-link-admin-help" class="icon icon-hilfe">Hilfe</a></li>

Obviously the css names should remain whatever they are in English, i.e. icon-structure, icon-appearance, etc.

Steps to reproduce:

• Enable German language
• Download and import interface translation from localize.drupal.org (latest 7.x works).
• (Add language switcher block + ) switch interface language to German