ART: Fix data loss when symbolizing oat files.

Change-Id: I1b40b8ee313a4d187439d969d083d12fb3997cda
diff --git a/compiler/buffered_output_stream.h b/compiler/buffered_output_stream.h
index bbc49df..15fc033 100644
--- a/compiler/buffered_output_stream.h
+++ b/compiler/buffered_output_stream.h
@@ -28,6 +28,7 @@
   explicit BufferedOutputStream(OutputStream* out);
 
   virtual ~BufferedOutputStream() {
+    Flush();
     delete out_;
   }