ART: Move JNI files to runtime/jni/ .

Test: Rely on TreeHugger.
Change-Id: I9cae11191ef1567ae9453be498882a7767285140
diff --git a/runtime/native/java_lang_Class.cc b/runtime/native/java_lang_Class.cc
index 2c1c963..2625c0a 100644
--- a/runtime/native/java_lang_Class.cc
+++ b/runtime/native/java_lang_Class.cc
@@ -28,7 +28,7 @@
 #include "dex/dex_file_annotations.h"
 #include "dex/utf.h"
 #include "hidden_api.h"
-#include "jni_internal.h"
+#include "jni/jni_internal.h"
 #include "mirror/class-inl.h"
 #include "mirror/class_loader.h"
 #include "mirror/field-inl.h"