This also changes the default number of mapper shards in tests to 2, which is
the number of EppResourceIndex buckets in unit tests. Running more shards than
there are buckets causes unnecessary test load.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=135520601
Now it lives alongside the delete prober data action, as well as any future
batch/maintenance tasks that should run periodically.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=134435668