Bug 1054326: Initial attempt to submit Imagecompare test framework and test cases int...

...o the main branch
hmm.. it appears that we have a logger reference in the runner but not the tests, could you file a bug against Marionette to pass the logger reference through to the test? you can then either leave these as print statements or first obtain a logger using:

```python
from mozlog.structured import get_default_logger
self.logger = get_default_logger()
```

Note that if you do this we should include a comment to remove it once we pass the logger from the test runner.