Enable debugging for tests

[xabitrigo]

I'm starting a project based on apollo-universal-starter-kit, and trying to make sense of the tests. To do it I tried to connect IntelliJ debugger to the tests execution, creating a debug configuration like this:

This runs the tests, but I cannot debug them. It complains about $NODE_DEBUG_OPTION, as I show next:

The objective is to be able to stop at the breakpoints to know what is happening there.