Disable shutdown

runtime/vm/service_isolate.cc

Index: runtime/vm/service_isolate.cc
diff --git a/runtime/vm/service_isolate.cc b/runtime/vm/service_isolate.cc
index 29a71ceb249ce7e4c8d81c52edfad7f05c53343e..39e457c8920de3ae00b58f93a1fd2949d9bc732a 100644
--- a/runtime/vm/service_isolate.cc
+++ b/runtime/vm/service_isolate.cc
@@ -22,6 +22,8 @@
 
 namespace dart {
 
+DECLARE_FLAG(bool, shutdown);
+
 #define Z (T->zone())
 
 
@@ -763,6 +765,9 @@ void ServiceIsolate::Run() {
 
 
 void ServiceIsolate::KillServiceIsolate() {
+  if (!FLAG_shutdown) {
+    return;
+  }
   {
     MonitorLocker ml(monitor_);
     shutting_down_ = true;