Issue 4450 - Prevent ElemHide filters with empty domains

test/elemHide.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 223 matching lines @@
   testResult("foo.com", []);
 
   addFilter("##hello");
   addFilter("foo.com##hello");
   testResult("foo.com", ["hello"]);
   removeFilter("##hello");
   testResult("foo.com", ["hello"]);
   removeFilter("foo.com##hello");
   testResult("foo.com", []);
 
-  // Advanced filter keys test
-  testResult("", []);
-  addFilter("##dupe");
-  addFilter(",,##dupe");
-  addFilter(",,,##dupe");
-  addFilter("foo.com##dupe");
-  testResult("", ["dupe"]);
-  removeFilter(",,,##dupe");
-  testResult("", ["dupe"]);
-  removeFilter("foo.com##dupe");
-  testResult("", ["dupe"]);
-  removeFilter(",,##dupe");
-  testResult("", ["dupe"]);
-  removeFilter("##dupe");
-  testResult("", []);
-
   test.done();
 };