ART: Move RegisterNatives helper

Move the helper closer to the users.

Test: m test-art-host
Change-Id: Id05ce5f60af54d0c5aef0c7d8932706c4602fc94
diff --git a/runtime/native/dalvik_system_DexFile.cc b/runtime/native/dalvik_system_DexFile.cc
index 870402d..ad00966 100644
--- a/runtime/native/dalvik_system_DexFile.cc
+++ b/runtime/native/dalvik_system_DexFile.cc
@@ -31,6 +31,7 @@
 #include "mirror/class_loader.h"
 #include "mirror/object-inl.h"
 #include "mirror/string.h"
+#include "native_util.h"
 #include "oat_file.h"
 #include "oat_file_assistant.h"
 #include "oat_file_manager.h"