Re-enable printing and timers in Dartium isolates

tests/html/html.status

Index: tests/html/html.status
diff --git a/tests/html/html.status b/tests/html/html.status
index ebb5278d21362ede8c1c420ca2980334d3f416fc..08f2a8112b449b02f666c51e97511235abd9c995 100644
--- a/tests/html/html.status
+++ b/tests/html/html.status
@@ -42,9 +42,8 @@ canvasrenderingcontext2d_test/drawImage_video_element_dataUrl: Pass,Fail # Issue
 [ $compiler == none && ($runtime == drt || $runtime == dartium || $runtime == ContentShellOnAndroid) ]
 # postMessage in dartium always transfers the typed array buffer, never a view
 postmessage_structured_test/typed_arrays: Fail
-# Dartium seems to lose the data from the dispatchEvent. 
+# Dartium seems to lose the data from the dispatchEvent.
 postmessage_structured_test/more_primitives: Fail
-async_test: Fail # Background timers not implemented.
 keyboard_event_test: Fail # Issue 13902
 isolates_test: Fail # Issue 13921
 indexeddb_3_test: Skip # Issue 19578.  Timeouts and RuntimeError
@@ -378,7 +377,6 @@ touchevent_test/supported: Fail
 xhr_test/xhr: Skip # Times out.  Issue 21527
 
 [ $compiler == none && $runtime == dartium ]
-async_test: Timeout # Issue 13719: Please triage this failure.
 element_offset_test/offset: Pass, Fail # Issue 13719, 13296
 
 [ $compiler == dartanalyzer || $compiler == dart2analyzer ]