Make valgrind happier and stop us leaking so much we can can't run the tests on a device.

Change-Id: Id8f45dde788fd84c10b0b5807b2d12eae529ba5e
diff --git a/src/reference_table.h b/src/reference_table.h
index 15a2e11..13317ea 100644
--- a/src/reference_table.h
+++ b/src/reference_table.h
@@ -33,6 +33,7 @@
 class ReferenceTable {
  public:
   ReferenceTable(const char* name, size_t initial_size, size_t max_size);
+  ~ReferenceTable();
 
   void Add(const Object* obj);