API: Explicitly track incompatibilities with previous API versions

Bug: 139128921
Test: make checkapi
Change-Id: I1f17b57705e2f7350b55ab278e06fc4e988771ff

Android.bp

@@ -1634,6 +1634,7 @@ droidstubs {
         last_released: {
             api_file: ":last-released-public-api",
             removed_api_file: "api/removed.txt",
+            baseline_file: ":public-api-incompatibilities-with-last-released",
         },
     },
     jdiff_enabled: true,
@@ -1659,6 +1660,7 @@ droidstubs {
         last_released: {
             api_file: ":last-released-system-api",
             removed_api_file: "api/system-removed.txt",
+            baseline_file: ":system-api-incompatibilities-with-last-released"
         },
     },
     jdiff_enabled: true,