[AIRFLOW-3804] Extend MySQL to GCS operator tests

[turbaszek]

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Jira

• My PR addresses the following Airflow Jira issues and references them in the PR title. For example, "[AIRFLOW-XXX] My Airflow PR"
  • https://issues.apache.org/jira/browse/AIRFLOW-3804

Description

• Here are some details about my PR, including screenshots of any UI changes:
  This commit adds additional test related to problem mentioned in initial issue https://issues.apache.org/jira/browse/AIRFLOW-3804
  I was not able to reproduce the mentioned behaviour but I think it's go to have these tests.

Tests

• My PR adds the following unit tests OR does not need testing for this extremely good reason:

Commits

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  1. Subject is separated from body by a blank line
  2. Subject is limited to 50 characters (not including Jira issue reference)
  3. Subject does not end with a period
  4. Subject uses the imperative mood ("add", not "adding")
  5. Body wraps at 72 characters
  6. Body explains "what" and "why", not "how"

Documentation

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  • All the public functions and the classes in the PR contain docstrings that explain what it does
  • If you implement backwards incompatible changes, please leave a note in the Updating.md so we can assign it to a appropriate release

Code Quality

• Passes flake8