Move numeric api files from frameworks/base to prebuilts/sdk

So they can be used in unbundled builds.

Bug: 7296240

Change-Id: I556f4eb1176d855c903a798e057df3b20e0e63f8
diff --git a/CtsCoverage.mk b/CtsCoverage.mk
index 61ad9c9..8d67a99 100644
--- a/CtsCoverage.mk
+++ b/CtsCoverage.mk
@@ -24,7 +24,7 @@
 
 coverage_out := $(HOST_OUT)/cts-api-coverage
 
-api_text_description := $(SRC_API_DIR)/current.txt
+api_text_description := frameworks/base/api/current.txt
 api_xml_description := $(coverage_out)/api.xml
 $(api_xml_description) : $(api_text_description) $(APICHECK)
 	$(hide) echo "Converting API file to XML: $@"