Fix the test loader

[Turbo87]

not ok 1 PhantomJS 2.1 - Global error: Error: Could not find module `ember` imported from `ember-resolver/resolver` at http://localhost:7357/assets/vendor.js, line 248
    ---
        Log: |
            { type: 'error',
              text: 'Error: Could not find module `ember` imported from `ember-resolver/resolver` at http://localhost:7357/assets/vendor.js, line 248\n' }
    ...
not ok 2 PhantomJS 2.1 - Global error: Error: Assertion Failed: The tests file was not loaded. Make sure your tests index.html includes "assets/tests.js". at http://localhost:7357/assets/vendor.js, line 16255
    ---
        Log: |
            { type: 'error',
              text: 'Error: Assertion Failed: The tests file was not loaded. Make sure your tests index.html includes "assets/tests.js". at http://localhost:7357/assets/vendor.js, line 16255\n' }
    ...
not ok 3 PhantomJS 2.1 - TestLoader Failures dummy/tests/integration/components/dummy-component-test: could not be loaded
    ---
        message: >
            Could not find module `ember` imported from `mocha`
        stack: >
            missingModule@http://localhost:7357/assets/vendor.js:248:93
            findModule@http://localhost:7357/assets/vendor.js:259:30
            findDeps@http://localhost:7357/assets/vendor.js:199:34
            findModule@http://localhost:7357/assets/vendor.js:262:19
            findDeps@http://localhost:7357/assets/vendor.js:199:34
            findModule@http://localhost:7357/assets/vendor.js:262:19
            requireModule@http://localhost:7357/assets/vendor.js:29:25
            require@http://localhost:7357/assets/test-support.js:19636:14
            loadModules@http://localhost:7357/assets/test-support.js:19628:21
            load@http://localhost:7357/assets/test-support.js:19658:33
            http://localhost:7357/assets/test-support.js:19546:20
        Log: |
    ...

not sure what's going on... I'm pretty sure that this has worked at some point, but Travis seems to disagree 😕