Fix chrome-qunit-test.js wasn't exiting with the right error code.

vendor/assets/javascripts/run-qunit-chrome.js

@@ -68,13 +68,13 @@ const CDP = require('chrome-remote-interface');
 
                 Runtime.evaluate({
                   expression: `(${check_script})()`
-                }).then((numFails) => {
+                }).then(numFails => {
                   if (numFails.result.type !== 'undefined') {
                     clearInterval(interval);
                     protocol.close();
                     chrome.kill();
 
-                    if (numFails.value > 0) {
+                    if (numFails.result.value > 0) {
                       process.exit(1);
                     } else {
                       process.exit();