clean up JS tests and integrate karma

- js:generate_runner now generates common files to be used by different test runners
- js spec file order now shuffled to better expose dependencies
- fakeENV now returns two methods: setup and teardown
- stock tinymce 3 files are now wrapped for AMD

test plan:

- tinymce should work the same
- js:test rake task should run tests
- js:build task should work as normal (using new location of r.js)
- test results should successfully send to firework

Change-Id: Ic09647f55dae57130fa0fe3d6a9168d2b67b89a2
Reviewed-on: https://gerrit.instructure.com/29297
QA-Review: Shawn Meredith <shawn@instructure.com>
Tested-by: Shawn Meredith <shawn@instructure.com>
Tested-by: Aaron Shafovaloff <ashafovaloff@instructure.com>
Reviewed-by: Aaron Shafovaloff <ashafovaloff@instructure.com>
Product-Review: Aaron Shafovaloff <ashafovaloff@instructure.com>
QA-Review: Aaron Shafovaloff <ashafovaloff@instructure.com>