R1:ec0085fd0c7a

Align "RevisionQuery->needCommitPHIDs()" to use Edges, not the legacy table

Summary:
Depends on D20458. Ref T13276. Although I'm not thrilled about "needCommitPHIDs()", it has a few callers, including custom fields. Allow "need + attach + get" to survive for now since they're reasonably modern, at least.

However, use edges instead of "TABLE_COMMIT" and require `need...()` + `get...()`, removing the direct `load...()`.

Also remove `RevisionQuery->withCommitPHIDs(...)`, which has no callers.

Test Plan…