Treat EventTarget as a secondary superclass

tests/html/html.status

Index: tests/html/html.status
diff --git a/tests/html/html.status b/tests/html/html.status
index fff6d67ac410d371a2b361db3f4390795543855e..0936ff15b3ab66729323daeb950a9e2c0f337320 100644
--- a/tests/html/html.status
+++ b/tests/html/html.status
@@ -25,23 +25,16 @@ audiobuffersourcenode_test: Pass, Fail, Crash # http://crbug.com/256601
 # postMessage in dartium always transfers the typed array buffer, never a view
 postmessage_structured_test/typed_arrays: Fail
 # TODO(vsm): Triage from latest Blink merge
-indexeddb_1_test: Skip
 indexeddb_2_test: Skip
 indexeddb_3_test: Skip
 indexeddb_4_test: Skip
 indexeddb_5_test: Skip
 js_test: Skip
-js_interop_2_test: Skip
 js_interop_4_test: Skip
-xhr_test: Skip
 crypto_test: Skip
 notifications_test: Skip
 dromaeo_smoke_test: Skip
 native_gc_test: Skip
-location_test: Skip
-history_test: Skip
-postmessage_structured_test: Skip # Timing out
-form_data_test: Skip # Timing out
 
 [ $compiler == none && $runtime == drt && $system == windows ]
 worker_test/functional: Pass, Crash # Issue 9929.