art: use proper nativehelper headers

libnativeheader exports headers under nativeheader. These were
available before incorrectly as global headers in order to give
access to jni.h.

Test: modules using art find headers
Bug: 63762847
Change-Id: I5c820d677e94e07b2859e78610bc997fe51b41dc
diff --git a/runtime/reflection.cc b/runtime/reflection.cc
index 532da2b..6f1d15c 100644
--- a/runtime/reflection.cc
+++ b/runtime/reflection.cc
@@ -28,10 +28,10 @@
 #include "mirror/class-inl.h"
 #include "mirror/executable.h"
 #include "mirror/object_array-inl.h"
+#include "nativehelper/ScopedLocalRef.h"
 #include "nth_caller_visitor.h"
 #include "scoped_thread_state_change-inl.h"
 #include "stack_reference.h"
-#include "ScopedLocalRef.h"
 #include "well_known_classes.h"
 
 namespace art {