Add more timing information in the VM to track time spent is dart code Vs native code.

runtime/vm/dart.cc

Index: runtime/vm/dart.cc
===================================================================
--- runtime/vm/dart.cc	(revision 32362)
+++ runtime/vm/dart.cc	(working copy)
@@ -191,8 +191,8 @@
 
 RawError* Dart::InitializeIsolate(const uint8_t* snapshot_buffer, void* data) {
   // Initialize the new isolate.
-  TIMERSCOPE(time_isolate_initialization);
   Isolate* isolate = Isolate::Current();
+  TIMERSCOPE(isolate, time_isolate_initialization);
   ASSERT(isolate != NULL);
   StackZone zone(isolate);
   HandleScope handle_scope(isolate);