CI: Setup automatic testing of the conda packages

[certik]

We have to setup automatic testing at a CI (in a new github project) to test the conda packages on all platforms, running our integration tests and ensuring they run correctly. That would reveal that it was missing lpython.py.

This should be done in a new separate github project.

[adam-urbanczyk]

I don't think that you need a separate project - you can simply extend tests in the conda package spec (see above).

[certik]

Thanks for the PR conda-forge/lpython-feedstock#16, that's much better than nothing.

What we also need is to test all our integration tests, not just one, which is what this issue is about.

[adam-urbanczyk]

I guess then it is a matter of adding python run_tests.py --skip-run-with-dbg to the test section. The point of the PR was to demonstrate that conda build is perfectly capable of running tests - no need to crate new projects

[certik]

We started a repository here: https://github.com/lcompilers/lpython-conda-testing, see lcompilers/lpython-conda-testing#1.