not ok 1 PhantomJS exited unexpectedly when running `ember test` on CI

Since updating to ember-cli 1.13.8 and Ember 2.0.0 (from 1.13.1 / 1.12.x) I can't get the test suite to run on CircleCI, because of the error:

not ok 1 PhantomJS - Browser "phantomjs /home/ubuntu/app-name/node_modules/ember-cli/node_modules/testem/assets/phantom.js http://localhost:7357/7887" exited unexpectedly.
1..1
tests 1
pass  0
fail  1
npm ERR! Test failed.  See above for more details.
npm test returned exit code 1

It used to work before and what is weird, it works locally (OS X El Capitan, PhantomJS 2.0). On CircleCI it also runs on 2.0 version which is installed the following way:

$ sudo apt-get update; sudo apt-get install libicu52
$ curl --output /home/ubuntu/bin/phantomjs-2.0.1-linux-x86_64-dynamic http://ift.tt/1PWWUr1
$ chmod a+x /home/ubuntu/bin/phantomjs-2.0.1-linux-x86_64-dynamic
$ sudo ln -s --force /home/ubuntu/bin/phantomjs-2.0.1-linux-x86_64-dynamic /usr/local/bin/phantomjs

Tried also downloading it from the Travis, but still the same thing happened.

Any idea what's the cause and how to solve it?