Add last-api files for intra core api

The build will now enforce these exist, so add some empty ones for now.

Bug: 176092454
Test: m nothing
Change-Id: I46bf7b0e80d85c2b84b07de77759abc11a254e23
diff --git a/android_icu4j/Android.bp b/android_icu4j/Android.bp
index 11e339b..9098f71 100644
--- a/android_icu4j/Android.bp
+++ b/android_icu4j/Android.bp
@@ -212,6 +212,22 @@
     no_dist: true,
 }
 
+// Referenced implicitly from i18n.module.intra.core.api.
+filegroup {
+    name: "i18n.module.intra.core.api.api.public.latest",
+    srcs: [
+        "api/intra/last-api.txt",
+    ],
+}
+
+// Referenced implicitly from i18n.module.intra.core.api.
+filegroup {
+    name: "i18n.module.intra.core.api-removed.api.public.latest",
+    srcs: [
+        "api/intra/last-removed.txt",
+    ],
+}
+
 // Referenced implicitly from legacy.i18n.module.platform.api.
 filegroup {
     name: "legacy.i18n.module.platform.api.api.public.latest",