move tests to run_test.py for jupyter_core

[bollwyvl]

Checklist

• [x] Used a personal fork of the feedstock to propose changes
• [x] Bumped the build number (if the version is unchanged)
• [ ] Reset the build number to 0 (if the version changed)
• [ ] Re-rendered with the latest conda-smithy (Use the phrase code>@<space/conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• [x] Ensured the license file is being packaged.

References:

• might help https://github.com/conda-forge/jupyter_core-feedstock/pull/78#issuecomment-1734127193

Changes:

• [x] move tests to run_test.py
  • [x] detect pypy, don't run coverage
• [x] update pip args

[conda-forge-webservices[bot]]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[bollwyvl]

@conda-forge-admin please rerender