Fix synthetic (lint) inline comments for comment hiding

Summary: These could cause F442758.

Test Plan: {F442779}

Reviewers: btrahan, joshuaspence

Reviewed By: joshuaspence

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D13042

src/applications/differential/storage/DifferentialInlineComment.php

@@ -51,10 +51,16 @@ final class DifferentialInlineComment
   }
 
   public function supportsHiding() {
+    if ($this->getSyntheticAuthor()) {
+      return false;
+    }
     return true;
   }
 
   public function isHidden() {
+    if (!$this->supportsHiding()) {
+      return false;
+    }
     return $this->proxy->getIsHidden();
   }