Remove BUILT_TESTS_ZIP_PACKAGE's dependency on the image files

Change-Id: I99baaeffe099e8fbb9789fb01b26a9a563e1e90d
diff --git a/core/Makefile b/core/Makefile
index c7e5406..81699ee 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -1206,11 +1206,12 @@
 $(BUILT_TESTS_ZIP_PACKAGE): intermediates := $(intermediates)
 $(BUILT_TESTS_ZIP_PACKAGE): zip_root := $(intermediates)/$(name)
 
-# Depending on the images guarantees that the underlying
+# Depending on the dependencies of system image and userdata image.
+# But we don't need to really create them.
 # directories are up-to-date.
 $(BUILT_TESTS_ZIP_PACKAGE): \
-		$(BUILT_SYSTEMIMAGE) \
-		$(INSTALLED_USERDATAIMAGE_TARGET) \
+		$(FULL_SYSTEMIMAGE_DEPS) \
+		$(INTERNAL_USERDATAIMAGE_FILES) \
 		| $(ACP)
 	@echo "Package test files: $@"
 	$(hide) rm -rf $@ $(zip_root)