Don't check response header on request 3.

Author: mnot

tests/stale.mjs

@@ -95,8 +95,8 @@ export default {
           setup: true,
           pause_after: true,
           response_headers: [
-            ['Cache-Control', 'no-cache'],
-            ['ETag', '"def"']
+            ['Cache-Control', 'no-cache', false],
+            ['ETag', '"def"', false]
           ],
           expected_type: 'cached'
         },