Support runtime check of function types.

tests/lib/lib.status

Index: tests/lib/lib.status
diff --git a/tests/lib/lib.status b/tests/lib/lib.status
index 88cf41b85b71b3992e0041c0257631d630d32627..7cc55db75cc8ad07353ec71eff9f2597cfc99ef6 100644
--- a/tests/lib/lib.status
+++ b/tests/lib/lib.status
@@ -16,6 +16,9 @@ typed_data/float32x4_list_test: Fail, OK
 typed_data/float32x4_unbox_phi_test: Fail, OK
 typed_data/float32x4_unbox_regress_test: Fail, OK
 
+[ $compiler == dart2js && $checked ]
+async/catch_errors20_test: Fail # computeSignature is not generated.
+
 [ $compiler == dart2js && ($runtime == d8 || $runtime == ie9) ]
 typed_data/byte_data_test: Fail, OK # d8/ie9 doesn't support DataView
 
@@ -34,9 +37,6 @@ mirrors/reflect_uninstantiated_class_test: Fail # Issue 6490
 mirrors/superclass_test: Fail # Issue 6490
 mirrors/to_string_test: Fail # Issue 6490
 
-[ $compiler == dart2js && $checked ]
-async/stream_event_transform_test: Fail # Issue 7733.
-
 [ $compiler == dart2js && $jscl ]
 async/future_test: Fail # Timer interface not supported; dartbug.com/7728.
 async/slow_consumer2_test: Fail # Timer interface not supported; dartbug.com/7728.