marked wide stream tests as expected failures for mingw (iostreams)

[SVN r27894]

status/explicit-failures-markup.xml

@@ -496,6 +496,7 @@
         <mark-expected-failures>
             <test name="code_converter_test"/>
 			<toolset name="gcc-2.95.3-linux"/>
+			<toolset name="mingw"/>
             <note author="Jonathan Turkanis">
                 No wide stream support.
             </note>
@@ -503,6 +504,7 @@
         <mark-expected-failures>
             <test name="wide_stream_test"/>
 			<toolset name="gcc-2.95.3-linux"/>
+			<toolset name="mingw"/>
             <note author="Jonathan Turkanis">
                 No wide stream support.
             </note>