Export app certificates to Make for apkcerts list

Bug: 70669383
Test: m apkcerts-list contains framework-res.apk
Change-Id: I38af458e4262371c9c8368b5eebcff063a9bc359
diff --git a/java/androidmk.go b/java/androidmk.go
index 1115114..40ebe5b 100644
--- a/java/androidmk.go
+++ b/java/androidmk.go
@@ -180,6 +180,8 @@
 				if Bool(app.appProperties.Privileged) {
 					fmt.Fprintln(w, "LOCAL_PRIVILEGED_MODULE := true")
 				}
+
+				fmt.Fprintln(w, "LOCAL_CERTIFICATE :=", app.certificate.pem.String())
 			},
 		},
 	}