Mark sp_convertible, ip_convertible, wp_convertible as expected failures on Borland.

[SVN r51685]

status/explicit-failures-markup.xml

@@ -2838,6 +2838,13 @@ for more information.
             <toolset name="*"/>
             <note refid="40" author="Boris Gubenko"/>
         </mark-expected-failures>
+        <mark-expected-failures>
+            <test name="sp_convertible_test"/>
+            <test name="wp_convertible_test"/>
+            <test name="ip_convertible_test"/>
+            <toolset name="borland-*"/>
+            <note refid="31" author="Peter Dimov"/>
+        </mark-expected-failures>
    </library>
 
     <!-- spirit -->