mocha >= 4.0 correctly reports unhandledRejection on its own (#1299)

See: mochajs/mocha#2879

Author: IvanGoncharov

resources/mocha-bootload.js

@@ -7,8 +7,3 @@
 
 var chai = require('chai');
 chai.use(require('chai-subset'));
-
-process.on('unhandledRejection', function (error) {
-  console.error('Unhandled Promise Rejection:');
-  console.error(error && error.stack || error);
-});