Add tests for using an offscreen canvas for Chart.js. These tests are
almost identical to existing tests, but with offscreen canvas enabled.
Co-authored-by: David Winegar <david.winegar@getcruise.com>
JSON doesn't support functions which are needed to create scriptable options, so implement a very basic method to load a JavaScript file exporting the config in `module.exports`. Also rename test sources (remove the `jasmine.` prefix), cleanup `karma.conf.js` and add an example .js fixture config (bubble radius option).