test(legacyExtension): remove legacy extension test

test/node/legacyExtensionSupport.js

@@ -1,24 +0,0 @@
-/**
- * Created by Estevao on 06-06-2015.
- */
-require('source-map-support').install();
-var expect = require('chai').expect,
-    showdown = require('../bootstrap').showdown;
-
-describe('showdown legacy extension support', function () {
-  'use strict';
-  var extObjMock =
-      {
-        type: 'lang',
-        filter: function () {}
-      },
-      extFunc = function () {
-        return [extObjMock];
-      };
-
-  it('accept extensions loaded by the old mechanism', function () {
-    showdown.extensions.bazinga = extFunc;
-    var cnv = new showdown.Converter({extensions: ['bazinga']});
-    expect(cnv.getAllExtensions().language).to.eql([extObjMock]);
-  });
-});