Sort burnup data chronologically after merging synthetic and "real" data

Summary:
Ref T13020. See PHI273. See D18853. On `secure`, the chart looks less promising than it did locally, and is full of discontinuities:

{F5356544}

I think this is a sorting issue. But if I can't fake my way through this soon I'll maybe get the Fact engine running and use it to provide the data here, as a sort of half-step toward T1562?

Test Plan: Chart looks the same locally, will push and see if `secure` improves?

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13020

Differential Revision: https://secure.phabricator.com/D18854

src/applications/maniphest/controller/ManiphestReportController.php

@@ -153,6 +153,7 @@ final class ManiphestReportController extends ManiphestController {
     // Merge the synthetic rows into the real transactions.
     $data = array_merge($create_rows, $data);
     $data = array_values($data);
+    $data = isort($data, 'dateCreated');
 
     $stats = array();
     $day_buckets = array();