Don't slice if parentBase has just one element.

require('ember-qunit') was failing because we couldn't  find module 'isolated-container'.

ember-qunit allow us to do require('ember-qunit') which "imports isolatedContainer from './isolated-container"

When requiring, the loader was calling "resolve" with
child="./isolatedContainer" and name = "ember-qunit", resolving to
'isolated-container' which is wrong, the reason?

 "ember-qunit".split('/').slice("/") === []

Is this is a case we didn't handle or are parents (name) suppose to
have "/"?