test: test configure ninja

- Updated the tooltest target to run unittest module
- Renamed test/tools/test-js2c.py to be discoverable by unittest module
- Added test class for `configure` shell script
- Added a test to ensure `configure` script exits with status code zero
when passed the `--ninja` flag

Closes: https://github.com/nodejs/node/issues/29415

PR-URL: https://github.com/nodejs/node/pull/30033


Reviewed-By: Sam Roberts <vieuxtech@gmail.com>
Reviewed-By: Christian Clauss <cclauss@me.com>