Avoid NaN percentage passed when nothing ran

[davidjgoss]

🤔 What's changed?

Don't attempt to do a 0 / 0 percentage calculation if no test cases ran.

⚡️ What's your motivation?

Fixes #362.

🏷️ What kind of change is this?

• 🐛 Bug fix (non-breaking change which fixes a defect)

📋 Checklist:

• I agree to respect and uphold the Cucumber Community Code of Conduct
• I've changed the behaviour of the code
  • I have added/updated tests to cover my changes.
• My change requires a change to the documentation.
  • I have updated the documentation accordingly.
• Users should know about my change
  • I have added an entry to the "Unreleased" section of the CHANGELOG, linking to this pull request.

---

This text was originally generated from a template, then edited by hand. You can modify the template here.

[netlify]

✅ Deploy Preview for cucumber-react-preview ready!

Name	Link
🔨 Latest commit	007746e
🔍 Latest deploy log	https://app.netlify.com/sites/cucumber-react-preview/deploys/67923ae07398290008f57b67
😎 Deploy Preview	https://deploy-preview-363--cucumber-react-preview.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[netlify]

✅ Deploy Preview for cucumber-react-preview ready!

Name	Link
🔨 Latest commit	84a59c9
🔍 Latest deploy log	https://app.netlify.com/sites/cucumber-react-preview/deploys/67923b5a7ec7b100080ea3f1
😎 Deploy Preview	https://deploy-preview-363--cucumber-react-preview.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.