Ability to run unit tests with `--bundle`

[rosen-vladimirov]

Is your feature request related to a problem? Please describe.
Currently I'm building and running my application with --bundle, i.e. with Webpack. However, this is not working for unit tests. This way I'm not sure my services are tested in the same way as when they'll be used at runtime in the actual application.

Describe the solution you'd like
Allow running tns test <platform> --bundle.

Describe alternatives you've considered
No

[Yermo]

I am also running into the same problem.