cmd-cloud-prune: Add tombstone-builds into builds count

Add the deleted builds into the total number of builds from
the builds.json when asserting that the size of builds array
is the same in the original and our modified builds.json

src/cmd-cloud-prune

@@ -277,8 +277,10 @@ def handle_upload_builds_json(s3_client, bucket, prefix, dry_run, acl):
 
     with open(BUILDFILES['sourcedata'], 'r') as file:
         builds_json_source_data = json.load(file)
-    # Make sure the size of the builds array is the same in the original and our modified builds.json
-    assert len(builds_json_source_data.get('builds')) == len(updated_builds_json.get('builds'))
+    # Make sure the size of the builds+tombstone-builds array is the same in the original and our modified builds.json
+    source_builds_count = len(builds_json_source_data.get('builds', [])) + len(builds_json_source_data.get('tombstone-builds', []))
+    updated_builds_count = len(updated_builds_json.get('builds', [])) + len(updated_builds_json.get('tombstone-builds', []))
+    assert source_builds_count == updated_builds_count
 
     # Before uploading builds.json, copy the updated tmp/builds-source.json as builds.json.bak as a backup
     s3_copy(s3_client, BUILDFILES['sourcedata'], bucket, f'{prefix}/builds.json.bak', CACHE_MAX_AGE_METADATA, acl, extra_args={}, dry_run=dry_run)