fix: respect nsconfig file on tns test command

[Fatme]

Rel to:
NativeScript/nativescript-angular#1310
#4244

PR Checklist

• The PR title follows our guidelines: https://github.com/NativeScript/NativeScript/blob/master/CONTRIBUTING.md#commit-messages.
• There is an issue for the bug/feature this PR is for. To avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it.
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• Tests for the changes are included.

What is the current behavior?

The user is not able to execute tns test command out of the box for new ng project

What is the new behavior?

The user is able to execute tns test command out of the box for new ng project

Should be merged with this PR: NativeScript/nativescript-unit-test-runner#28