Flake8 remaining Python integration tests

This completes the flake8 fixing of the Python integration tests. The tests should still pass barring the usual intermittent fails, they should all pass flake8 checks.
Excellent! This is the same fail as I had locally, 10.8.5, Ice 3.5. I am (sort of) pleased that it has been reproduced. The test can be passed by adding `Ice.UnknownLocalException` to the two `with pytest.raises()` lines in this test. However, I am reticent to do that without understanding the underlying cause of the change. I.e. should something else be happening server-side at the point where this exception is first raised? /cc @joshmoore