Use the Finder's results for faster searching

Bug: 64363847
Test: m -j

Change-Id: Ie0905d8c5c54cd4c0c3b3edda6c3f1c4135ed7ed
diff --git a/core/cleanspec.mk b/core/cleanspec.mk
index 4441e2a..af28954 100644
--- a/core/cleanspec.mk
+++ b/core/cleanspec.mk
@@ -64,6 +64,6 @@
 # ************************************************
 
 subdir_cleanspecs := \
-    $(shell build/tools/findleaves.py $(FIND_LEAVES_EXCLUDES) . CleanSpec.mk)
+    $(file <$(OUT_DIR)/.module_paths/CleanSpec.mk.list)
 include $(subdir_cleanspecs)
 subdir_cleanspecs :=