Display slowest tests in PR

Sentry Feedback: [GAZEBO-16Y7](https://codecov.sentry.io/feedback/?referrer=github_integration&feedbackSlug=gazebo%3A6707983963&project=5514400)

Can the github comment on a PR include the top 10 slowest tests?

|  |  |
| ------------- | --------------- |
| **contact_email** | tylerzey@gmail.com |
| **name** | tylerzey |