Tests: Fix failing ajax tests in oldIE

(cherry-picked from the 7178096507)

Picked up so tests from the 1.x-master would be more similar to this branch

test/data/test.html

@@ -3,5 +3,5 @@ html text<br/>
 testFoo = "foo"; jQuery('#foo').html('foo');
 ok( true, "test.html executed" );
 /* ]]> */</script>
-<script src="data/test.js"></script>
+<script src="data/testbar.php"></script>
 blabla