Issue #1498 - Part 4: Remove clearPreloads.

Also tag #1280

testing/marionette/cert.js

@@ -134,7 +134,6 @@ cert.InsecureSweepingOverride = function() {
       // clear collected HSTS and HPKP state
       // through the site security service
       sss.clearAll();
-      sss.clearPreloads();
     },
   };
 };