Summary:
Depends on D20292. Ref T13259. This converts the rest of the `getPagingValueMap()` callsites to operate on internal cursors instead.

These are pretty one-off for the most part, so I'll annotate them inline.

Test Plan:
  - Grouped tasks by project, sorted by title, paged through them, saw consistent outcomes.
  - Queried edges with "edge.search", paged through them using the "after" cursor.
  - Poked around the other stuff without catching any brokenness.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13259

Differential Revision: https://secure.phabricator.com/D20293