Remove Controller->getHandle() and Controller->loadHandles()

Summary: Ref T7689. Modernize all callsites of these methods.

Test Plan:
- Poked at dashboards.
  - Pretty sure this code is technically unreachable right now.
- Viewed commit; viewed "Audit Status".
- Viewed a fund; viewed "Payable to"; viewed "Owner".
- Viewed herald rules; viewed "Author"; viewed "Applies To".
- Viewed a Legalpad document; viewed "Contributors".
- Viewed Phame post list; viewed blog; viewed post (viewed "Blog", viewed "Blogger").
- Viewed a macro; viewed "Audio".
- Viewed a Phriction page; viewed "Last Author".
- Viewed a Ponder question; viewed "Author".
- Viewed a Ponder answer; viewed header.
  - Behavior changed very slightly here; whatevs.
- Viewed a Countdown; viewed "Author".

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T7689

Differential Revision: https://secure.phabricator.com/D12210

src/applications/base/controller/PhabricatorController.php

@@ -426,20 +426,6 @@ abstract class PhabricatorController extends AphrontController {
     return $response;
   }
 
-  protected function getHandle($phid) {
-    if (empty($this->handles[$phid])) {
-      throw new Exception(
-        "Attempting to access handle which wasn't loaded: {$phid}");
-    }
-    return $this->handles[$phid];
-  }
-
-  protected function loadHandles(array $phids) {
-    $phids = array_filter($phids);
-    $this->handles = $this->loadViewerHandles($phids);
-    return $this;
-  }
-
   protected function loadViewerHandles(array $phids) {
     return id(new PhabricatorHandleQuery())
       ->setViewer($this->getRequest()->getUser())