fix window width problem; closes #4393

looks like maybe a bad merge, but `isBrowser()` was used incorrectly

Author: boneskull

lib/reporters/base.js

@@ -14,7 +14,7 @@ var constants = require('../runner').constants;
 var EVENT_TEST_PASS = constants.EVENT_TEST_PASS;
 var EVENT_TEST_FAIL = constants.EVENT_TEST_FAIL;
 
-var isBrowser = require('../utils').isBrowser;
+const isBrowser = utils.isBrowser();
 
 function getBrowserWindowSize() {
   if ('innerHeight' in global) {
@@ -34,7 +34,7 @@ exports = module.exports = Base;
  * Check if both stdio streams are associated with a tty.
  */
 
-var isatty = isBrowser ? true : process.stdout.isTTY && process.stderr.isTTY;
+var isatty = isBrowser || (process.stdout.isTTY && process.stderr.isTTY);
 
 /**
  * Save log references to avoid tests interfering (see GH-3604).
@@ -46,7 +46,7 @@ var consoleLog = console.log;
  */
 
 exports.useColors =
-  !utils.isBrowser() &&
+  !isBrowser &&
   (supportsColor.stdout || process.env.MOCHA_COLORS !== undefined);
 
 /**