Move the test scripts

[ppolewicz]

move b2sdk/account_info/test_upload_url_concurrency.py and test_raw_api, test_raw_api_helper, _clean_and_delete_bucket, _should_delete_bucket, _add_range_header from b2sdk/raw_api.py to somewhere else, so that we can still execute them in pre-commit.sh, but so that it does not get test coverage tracking and so that it is not shipped in the package to the library user

[mjurbanski-reef]

outdated - we don't even use pre-commit.sh anymore; Any reorganization of test code should be done as part of #191 .