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_test.cc b/runtime/reflection_test.cc
index 1ba4b7b..5eb75ed 100644
--- a/runtime/reflection_test.cc
+++ b/runtime/reflection_test.cc
@@ -18,13 +18,13 @@
 
 #include <float.h>
 #include <limits.h>
-#include "ScopedLocalRef.h"
 
 #include "art_method-inl.h"
 #include "base/enums.h"
 #include "common_compiler_test.h"
 #include "java_vm_ext.h"
 #include "jni_internal.h"
+#include "nativehelper/ScopedLocalRef.h"
 #include "scoped_thread_state_change-inl.h"
 
 namespace art {