Review use of CLI for stripes-components test

As part of the reduced performance observed following the webpack 4 upgrade, it was noted that building stripes-components for tests is particularly slow. This may be in part due to the CLI automatically building a "virtual platform" with each call to stripes test karma. This is a required step for an entire app like eholdings, but may not be necessary for more isolated stripes-components tests.

Review the stripes test karma command sequence and, if necessary, introduce an option to skip building the virtual platform prior to invoking tests.