Upload compatibility test jars to release folder (#2873)

We need to stop using maven repo on GCS to store artifacts for the
schema compatibility tests. After public access is removed from GCS
buckets, Kokoro won't be able to access it: normal access will be
denied, and the repo is too large to map (copy) to Kokoro VM as a
resource.

This PR uploads the relevant jars to each release's folder. See
go/dr-gcs-public-access-prevention for details.

release/cloudbuild-nomulus.yaml

@@ -177,10 +177,11 @@ steps:
       -PpluginsUrl=gcs://domain-registry-maven-repository/plugins \
       -Ppublish_repo=gcs://${PROJECT_ID}-deployed-tags/maven \
       -Pnomulus_version=${TAG_NAME}
-    # Upload schema jar for use by schema deployment.
-    # TODO(weiminyu): consider using the jar in maven repo during deployment and
-    # stop the  upload here.
+    # Upload jars for use by schema deployment and schema compatibility test.
+    # The jars published to GCS will be unaccessible to Kokoro once public access is removed.
     cp db/build/libs/schema.jar output/
+    cp core/build/libs/nomulus-public.jar output/
+    cp core/build/libs/nomulus-tests-alldeps.jar output/
 # The tarballs and jars to upload to GCS.
 artifacts:
   objects:
@@ -189,6 +190,8 @@ artifacts:
     - 'output/*.tar'
     - 'output/tag_name'
     - 'output/nomulus.jar'
+    - 'output/nomulus-public.jar'
+    - 'output/nomulus-tests-alldeps.jar'
     - 'output/schema.jar'
     - 'core/src/main/java/google/registry/config/files/nomulus-config-*.yaml'
     - 'core/src/main/java/google/registry/config/files/cloud-tasks-queue.xml'