Move web-platform-tests to wpt (part 2 of 2)

third_party/WebKit/LayoutTests/imported/wpt/webstorage/event_setattribute.js

 testStorages(function(storageString) {
     async_test(function(t) {
         assert_true(storageString in window, storageString + " exist");
         var storage = window[storageString];
         t.add_cleanup(function() { storage.clear() });
 
         clearStorage(storageString, t.step_func(step0));
         assert_equals(storage.length, 0, "storage.length");
 
         function step0(msg)
@@ skipping 95 matching lines @@
             assert_equals(storageEventList.length, 8);
             assert_equals(storageEventList[7].key, null);
             assert_equals(storageEventList[7].oldValue, null);
             assert_equals(storageEventList[7].newValue, null);
 
             t.done();
         }
 
     }, storageString + " mutations fire StorageEvents that are caught by the event listener attached via setattribute.");
 });