Instantiate Runner earlier in Mocha constructor

lib/mocha.js

@@ -91,6 +91,8 @@ exports.Test = require('./test');
  * @param {string} [options.ui] - Interface name.
  * @param {boolean} [options.color] - Color TTY output from reporter?
  * @param {boolean} [options.useInlineDiffs] - Use inline diffs?
+ * @prop {Suite} suite - Root Suite instance
+ * @prop {Runner} runner - Runner instance
  */
 function Mocha(options) {
   options = utils.assign({}, mocharc, options || {});
@@ -153,6 +155,8 @@ function Mocha(options) {
       this[opt]();
     }
   }, this);
+
+  this.runner = new exports.Runner(this.suite, options.delay);
 }
 
 /**
@@ -803,10 +807,9 @@ Mocha.prototype.run = function(fn) {
   if (this.files.length) {
     this.loadFiles();
   }
-  var suite = this.suite;
   var options = this.options;
   options.files = this.files;
-  var runner = new exports.Runner(suite, options.delay);
+  var runner = this.runner;
   createStatsCollector(runner);
   var reporter = new this._reporter(runner, options);
   runner.ignoreLeaks = options.ignoreLeaks !== false;