isolates refactor: this change introduces 'dart:isolate' as a library. This is a

tests/isolate/isolate.status

Index: tests/isolate/isolate.status
diff --git a/tests/isolate/isolate.status b/tests/isolate/isolate.status
index e64b95be1571477b7725ed6c98dc9d8d69fbe512..e1b0a764d00310cb8d4abc9c48bbda446da57622 100644
--- a/tests/isolate/isolate.status
+++ b/tests/isolate/isolate.status
@@ -8,10 +8,11 @@ prefix isolate
 Isolate2NegativeTest: Skip  # Need to resolve correct behaviour.
 
 [ $component == dartium || $component == vm ]
-SerializationTest: Skip  # DartC test (uses coreimpl).
+SerializationTest: Skip  # tests frog-specific serialization code
 *APIv2*: Skip # new api for isolates not implemented in the VM yet.
 
 [ $component == dartc ]
+SerializationTest: Skip  # tests frog-specific serialization code
 IsolateNegativeTest: Fail    # status change with --check-only
 Isolate2NegativeTest: Fail   # status change with --check-only
 *APIv2*: Skip # new api for isolates not in corelib yet.