Add isolate event handler setup in order to be able to propagate isolate

vm/isolate.cc

Index: vm/isolate.cc
===================================================================
--- vm/isolate.cc	(revision 13083)
+++ vm/isolate.cc	(working copy)
@@ -234,6 +234,9 @@
   result->set_main_port(PortMap::CreatePort(result->message_handler()));
   result->BuildName(name_prefix);
 
+  // Signal isolate creation event.
+  Debugger::SignalIsolateEvent(Debugger::kIsolateCreated);
+
   result->debugger_ = new Debugger();
   result->debugger_->Initialize(result);
   if (FLAG_trace_isolates) {
@@ -411,6 +414,9 @@
     debugger_->Shutdown();
   }
 
+  // Signal isolate shutdown event.
+  Debugger::SignalIsolateEvent(Debugger::kIsolateShutdown);
+
   // Close all the ports owned by this isolate.
   PortMap::ClosePorts(message_handler());