- changed config.xml/yaml files used by CH's own internal tests which
are (hopefully) not sensitive to mark_cache_size being set or not
- further occurrences exist but changing them seems a bad idea (e.g.
because they are in customer-provided data)
This PR formats all the `*.py` files found under the `tests/integration`
folder. It also reorders the imports and cleans up a bunch of unused
imports.
The formatting also takes care of other things like wrapping lines and
fixing spaces and indents such that the tests look more readable.
Mikhail Artemenko