[Fetch] Split layout tests

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

Index: LayoutTests/http/tests/serviceworker/resources/fetch-access-control-util.js
diff --git a/LayoutTests/http/tests/serviceworker/resources/fetch-access-control-util.js b/LayoutTests/http/tests/serviceworker/resources/fetch-access-control-util.js
index e9b67a6b3024c91f6b975ee7f95d211cd79718c6..09dbf29a81700ba8b3935302f94ac95bf0878d46 100644
--- a/LayoutTests/http/tests/serviceworker/resources/fetch-access-control-util.js
+++ b/LayoutTests/http/tests/serviceworker/resources/fetch-access-control-util.js
@@ -368,6 +368,9 @@ function report(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);