Preload DexCaches

Bug: 11045348
Change-Id: I6f9c0d11613b6b4933a04ae23dbf4bc7879cea65
diff --git a/runtime/runtime.h b/runtime/runtime.h
index bc5c8b0..7c28479 100644
--- a/runtime/runtime.h
+++ b/runtime/runtime.h
@@ -279,6 +279,7 @@
   }
 
   InternTable* GetInternTable() const {
+    DCHECK(intern_table_ != NULL);
     return intern_table_;
   }