Fix indirect miuse of $(my-dir).

Change-Id: I075938a7bcbe66aac7c6d0ab874ed8816a89a2c9
diff --git a/Android.mk b/Android.mk
index 7fa96d0..4514f94 100644
--- a/Android.mk
+++ b/Android.mk
@@ -10,4 +10,4 @@
 include $(LOCAL_PATH)/build-config.mk
 include $(LOCAL_PATH)/Scrypt.mk
 
-include $(call all-named-subdir-makefiles,tests)
+include $(LOCAL_PATH)/tests/Android.mk