Don't build tests by default

Change-Id: I30de838657199b853948b6ba77bc9e5da28cc4f7
diff --git a/Android.mk b/Android.mk
index 8b6532c..023e0c0 100644
--- a/Android.mk
+++ b/Android.mk
@@ -21,4 +21,6 @@
 include $(BUILD_PACKAGE)
 
 # Use the folloing include to make our test apk.
+ifeq (,$(ONE_SHOT_MAKEFILE))
 include $(call all-makefiles-under,$(LOCAL_PATH))
+endif