Test runner reports failure when contrib project has no automated tests but automated testing is enabled

Problem/Motivation

The test runner returns a failure on a contrib project when tests are enabled, but the project has no automated tests. This does not match the behavior described in #2645590: Ensure that simpletest job doesn't "fail" testing if no tests are present :

projects with no tests will now return a "No tests Found" and be green if the build is successful

https://www.drupal.org/project/drupalci_testbot/issues/2645590#comment-1...

Example issue: #2990836: Follow Drupal coding standards
Job URL: https://www.drupal.org/pift-ci-job/1035442

Proposed resolution

Projects with no tests will now return a "No tests Found" and be green if the build is successful

Remaining tasks

To be determined.

User interface changes

To be determined.

API changes

To be determined.

Data model changes

To be determined.