Example for running JS Tests with Multiplatform Plugin

[ScottPierce]

Common Tests don't actually run for JS modules. I noticed it locally, and then I was able to confirm the same result on the lib-with-tests module example provided in this repo. If I add a failing test to a common module, and then run the jsTest command, the tests won't actually be run, and the build will pass.

[DrewCarlson]

For what it's worth, here are some examples of testing js targets with mocha and qunit.