ART: Move JNI files to runtime/jni/ .

Test: Rely on TreeHugger.
Change-Id: I9cae11191ef1567ae9453be498882a7767285140
diff --git a/runtime/native/java_lang_Object.cc b/runtime/native/java_lang_Object.cc
index d52bf04..208ccf6 100644
--- a/runtime/native/java_lang_Object.cc
+++ b/runtime/native/java_lang_Object.cc
@@ -18,7 +18,7 @@
 
 #include "nativehelper/jni_macros.h"
 
-#include "jni_internal.h"
+#include "jni/jni_internal.h"
 #include "mirror/object-inl.h"
 #include "native_util.h"
 #include "scoped_fast_native_object_access-inl.h"