marked stream_offset_64bit_test as an expected failure on vacpp (iostreams)

[SVN r42644]

status/explicit-failures-markup.xml

@@ -2037,6 +2037,14 @@
                 conversion state; on this platform, long is a 32-bit type
             </note>
         </mark-expected-failures>
+        <mark-expected-failures>
+            <test name="stream_offset_64bit_test"/>
+            <toolset name="vacpp*"/>
+            <note author="Jonathan Turkanis" date="09 Jan 2008">
+                This platform uses the Dinkumware fpos, but std::streamsize and
+                std::fpos_t are both 32-bit types.
+            </note>
+        </mark-expected-failures>
     </library>
 
     <!-- lambda -->