Update explicit-failures-markup.xml

[skip ci]

status/explicit-failures-markup.xml

@@ -591,12 +591,6 @@
                 <note author="Jeremy Siek"/>
             </mark-failure>
         </test>
-        <test name="stl_concept_covering">
-            <mark-failure>
-                <toolset name="*"/>
-                <note author="Jeremy Siek" refid="1"/>
-            </mark-failure>
-        </test>
         <test name="stl_concept_check">
           <mark-failure>
             <toolset name="hp_cxx*"/>