Corrected a frame test fixture

Author: aik099

web-fixtures/iframe.html

@@ -4,7 +4,7 @@
 
 <iframe src="iframe_inner.html" name="subframe_by_name"></iframe>
 
-<iframe src="issue131.html" name="subframe_by_id"></iframe>
+<iframe src="issue131.html" id="subframe_by_id"></iframe>
 
 <div id="text">
     Main window div text