Migrate Differential Revision SavedQueries to the new "statuses" tokenizer

Summary: Ref T2543. This migrates existing saved queries so they use the right modern values for the new tokenizer control, introduced in D18393.

Test Plan:

• Saved a query with "Abandoned" selected as the status in the old "<select />", prior to D18393.
• Upgraded to D18393, which broke the query (it no longer selected any status filter).
• Ran the migration to fix things.
• Saw the query now execute with "Abandoned" selected in the tokenizer, preseving the original behavior accurately.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T2543

Differential Revision: https://secure.phabricator.com/D18394