Fix reuse of free blocks and delete global cache on VM shutdown.

runtime/vm/dart.cc

Index: runtime/vm/dart.cc
diff --git a/runtime/vm/dart.cc b/runtime/vm/dart.cc
index e5cd485be6968f8b33a0249711c33d859e719369..c8cf5593b073f58fb899446c9cb3dd6fa4f8c6f2 100644
--- a/runtime/vm/dart.cc
+++ b/runtime/vm/dart.cc
@@ -23,6 +23,7 @@
 #include "vm/service_isolate.h"
 #include "vm/simulator.h"
 #include "vm/snapshot.h"
+#include "vm/store_buffer.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 #include "vm/thread_interrupter.h"
@@ -220,6 +221,7 @@ const char* Dart::Cleanup() {
   Profiler::Shutdown();
   CodeObservers::DeleteAll();
   Timeline::Shutdown();
+  StoreBuffer::ShutDown();
 
   return NULL;
 }