Move Test class to its own test.py module

Make the code more reachable for newcomers, as well as more organized
for people who work a lot with it.

SuiteRun in suite.py is already quite big, and having the Test class in
there make it unnecessarily more big, and makes it difficult to find
stuff.

At the same time, having a test.py which does actually not contain the
Test class but other stuff, makes it even more confusing.

Change-Id: I9c8d67f598466ba52a4827ff77027b9eae85929a
4 files changed