Disable shutdown

BUG=

Review URL: https://codereview.chromium.org//1350713004 .
diff --git a/runtime/bin/process.cc b/runtime/bin/process.cc
index 3c345b7..9e3e14e 100644
--- a/runtime/bin/process.cc
+++ b/runtime/bin/process.cc
@@ -19,7 +19,7 @@
 
 // Global flag that is used to indicate that the VM should do a clean
 // shutdown.
-bool do_vm_shutdown = true;
+bool do_vm_shutdown = false;
 
 static const int kProcessIdNativeField = 0;
 
diff --git a/runtime/vm/dart.cc b/runtime/vm/dart.cc
index 9da4158..8d2a7da 100644
--- a/runtime/vm/dart.cc
+++ b/runtime/vm/dart.cc
@@ -38,7 +38,7 @@
 DECLARE_FLAG(bool, trace_time_all);
 DEFINE_FLAG(bool, keep_code, false,
             "Keep deoptimized code for profiling.");
-DEFINE_FLAG(bool, shutdown, true, "Do a clean shutdown of the VM");
+DEFINE_FLAG(bool, shutdown, false, "Do a clean shutdown of the VM");
 
 Isolate* Dart::vm_isolate_ = NULL;
 ThreadPool* Dart::thread_pool_ = NULL;
diff --git a/runtime/vm/service_isolate.cc b/runtime/vm/service_isolate.cc
index 29a71ce..39e457c 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::KillServiceIsolate() {
+  if (!FLAG_shutdown) {
+    return;
+  }
   {
     MonitorLocker ml(monitor_);
     shutting_down_ = true;