R1:2b9838b482af

Modularize remaining TYPE_ACTION transactions in Differential, reducing calls to ArcanistDifferentialRevisionStatus

Summary:
Ref T2543. This cleans up a couple of remaining rough edges:

- We could do an older TYPE_ACTION "close" via the daemons.
- We could do an older TYPE_ACTION "close" via `arc close-revision`, explicitly or implicitly in `arc land`, via API (`differential.close`).
- We could do an older TYPE_ACTION "rethink" ("Plan Changes") via the API, via `arc diff --plan-changes`…