fix: removed/ignore tests/fn-root-vars.out as it is recreated by run_example.sh every time.
Every time I run "make tests" on a fresh HEAD the file fn-root-vars.out changes with my home folder path written to that. This due to this section of run_examples.sh.
Since the file is overwritten every test run. There is no need to keep it in the respo. It also ensures no accidentally committed overwritten fn-root-vars.out anymore.