Fix errors in start with URL tests

tools/perf/page_sets/startup_pages_record.json

 {
   "description": 
   ["Pages to record data for testing starting Chrome with a URL. We can't use",
    "startup_pages.json with record_wpr, since record_wpr requires a default", 
    "navigate step, which we don't want for startup testing; but we do want to",
    "record the pages it uses.",
    "Also, record_wpr fails on about:blank, which we want to include in startup", 
    "testing."],
   "archive_data_file": "data/startup_pages.json",
   "pages": [
     {
-      "url": "http://news.bbc.co.uk",
+      "url": "http://bbc.co.uk",
       "why": "typical page"
     },
     {
       "url": "http://kapook.com",
       "why": "Horribly complex page - stress test!"
     }
   ]
 }