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/openjdkjvmti/events-inl.h b/runtime/openjdkjvmti/events-inl.h
index f30d7ce..43177ab 100644
--- a/runtime/openjdkjvmti/events-inl.h
+++ b/runtime/openjdkjvmti/events-inl.h
@@ -21,7 +21,7 @@
 
 #include "events.h"
 #include "jni_internal.h"
-#include "ScopedLocalRef.h"
+#include "nativehelper/ScopedLocalRef.h"
 #include "ti_breakpoint.h"
 
 #include "art_jvmti.h"