Error messages get swallowed when running all test suites at once

[johnbillion]

Steps to reproduce:

1. Follow the setup instructions in Integration tests erroring with "The site you have requested is not installed" #347
2. Instead of running just the integration test suite, run all the tests with composer dev-tools codecept run
3. Observe that the integration suite still triggers an exception, but the error message is not shown in the output
4. It's a mystery