[Fetch] Split layout tests

LayoutTests/http/tests/serviceworker/resources/fetch-access-control-util.js

 var SCOPE = BASE_ORIGIN +
   '/serviceworker/resources/fetch-access-control-iframe.html?' + TEST_OPTIONS;
 var IFRAME_ORIGIN = BASE_ORIGIN;
 var BASE_URL = BASE_ORIGIN +
   '/serviceworker/resources/fetch-access-control.php?';
 var OTHER_BASE_URL = OTHER_ORIGIN +
   '/serviceworker/resources/fetch-access-control.php?';
 var REDIRECT_URL = BASE_ORIGIN +
   '/serviceworker/resources/redirect.php?Redirect=';
 var OTHER_REDIRECT_URL = OTHER_ORIGIN +
@@ skipping 350 matching lines @@
     return Promise.resolve({fetchResult: 'error'});
   }
 }
 
 var report_data = {};
 function report(data) {
   report_data = data;
 }
 
 function executeTest(test_target) {
+  if (test_target.length == 0) {
+    return Promise.resolve();
+  }
   return doFetch(test_target[0])
     .then(function(message) {
         var checks = test_target[1].concat(showComment);
         checks.forEach(function(checkFunc) {
             checkFunc.call(this, test_target[0], message);
           });
 
         if (test_target[2]) {
           report_data = {};
           if (message.fetchResult !== 'resolved' ||
@@ skipping 30 matching lines @@
             return executePromiseTest(test_targets[counter],
                                       "executeTest-" + counter);
           }.bind(this, i)).catch(function(e) {
             // The error was already reported. Continue to the next test.
           });
       }
       promise.then(function() {t.done();});
     },
     'executeTests');
 }