Fixes flakey local assertion

[ryanlabouve]

I kept running into the issue locally where the data.startTime and data.endTime would be exactly the same in unit test and cause the test suite to randomly fail.

Can we instead test for >=?

[ryanlabouve]

Specifically failing here:

ember-perf/tests/unit/services/ember-perf-test.js

Line 34 in 19e1ad3

test('measureRender returns a promise', function(assert) {

[ryanlabouve]

Seems like we are getting an unrelated failure from Travis:

 [0417/015914.079769:FATAL:setuid_sandbox_host.cc(157)] The SUID sandbox helper binary was found, but is not configured correctly. Rather than run without sandboxing I'm aborting now. You need to make sure that /opt/google/chrome/chrome-sandbox is owned by root and has mode 4755.