document.lastModified should consider user's local time zone

LayoutTests/http/tests/resources/last-modified.php

Index: LayoutTests/http/tests/resources/last-modified.php
diff --git a/LayoutTests/http/tests/resources/last-modified.php b/LayoutTests/http/tests/resources/last-modified.php
index 55c52220de5e06af50c4e8e46e48a66d7f9b3a19..6465f77cd6133177b723e53ed6f3aa057d343161 100644
--- a/LayoutTests/http/tests/resources/last-modified.php
+++ b/LayoutTests/http/tests/resources/last-modified.php
@@ -1,7 +1,14 @@
 <?php
     $date = $_GET['date'];
+    $expected = $_GET['expected'];
     header("Last-Modified: $date");
 ?>
 <script>
-document.write(document.lastModified);
+var expected = '<?=$expected?>';
+var lastModified = document.lastModified;
+if (expected == lastModified) {
+    document.write('PASS');
+} else {
+    document.write('FAIL: expect ' + expected + ', but got ' + lastModified);
+}
 </script>