As previously written, it loaded up all history entries into memory and then
processed them. This was OOMing for some registrars on sandbox who had performed
a large number of testing actions, most of them long OT&E was passed.
This commit changes the verify OT&E action to stream the history entries in
batches, ordered by when they were made, and then terminates once all tests have
passed. This prevents OOMing because only a single batch of history entries need
reside in memory at once.
This does necessitate the creation of a new composite Datastore index on
HistoryEntry, so we'll need to run the ResaveAllHistoryEntriesAction in sandbox
after this change is deployed before the new verify OT&E code will work.
Note that the "history viewer" is long dead, but that the pre-existing index
on HistoryEntries is still used for many other purposes.
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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=223163337
c2ee453745