Mark more custom tests as flaky.

tests/html/html.status

Index: tests/html/html.status
diff --git a/tests/html/html.status b/tests/html/html.status
index 0e256b0bd3f485e1b55d7d3b98bcba9df2967e20..d40b88ae7b9069b8f5e8cabf4d93fb7f5061e5ff 100644
--- a/tests/html/html.status
+++ b/tests/html/html.status
@@ -67,7 +67,9 @@ xhr_test/json: Fail # TODO(dart2js-team): Please triage this failure.
 async_test: Pass, Fail # timers test fails on ie10.
 indexeddb_5_test: Fail # Issue 12893
 js_test: Fail # Issue 14246
-custom/constructor_calls_created_synchronously_test: Fail, Pass # Issue 16453
+custom/constructor_calls_created_synchronously_test: Fail, Pass # Issue 16441
+custom_elements_test/innerHtml: Fail, Pass # Issue 16441
+custom_elements_test/lifecycle: Fail, Pass # Issue 16441
 
 [ $compiler == dart2js && ( $runtime == ie9 || $runtime == ie10 ) ]
 worker_api_test: Fail # IE does not support URL.createObjectURL in web workers.
@@ -176,7 +178,7 @@ xhr_test/json: Fail # IE9 returns null because of unsupported type
 js_test: RuntimeError # Issue 14645
 custom/mirrors_test: pass, fail # Issue 16441
 custom/constructor_calls_created_synchronously_test: pass, fail # Issue 16441
-custom/document_register_basic_test: pass, fail # Issue 16455
+custom/document_register_basic_test: pass, fail # Issue 16441
 
 # IE9 Feature support statuses-
 # All changes should be accompanied by platform support annotation changes.