Update cxx_dr_status to cover dr1748 and add test.

llvm-svn: 229229
diff --git a/clang/www/cxx_dr_status.html b/clang/www/cxx_dr_status.html
index 03afa35..58450c0 100644
--- a/clang/www/cxx_dr_status.html
+++ b/clang/www/cxx_dr_status.html
@@ -10303,7 +10303,7 @@
     <td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1748">1748</a></td>
     <td>DR</td>
     <td>Placement new with a null pointer</td>
-    <td class="none" align="center">Unknown</td>
+    <td class="svn" align="center">SVN</td>
   </tr>
   <tr id="1749">
     <td><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_closed.html#1749">1749</a></td>