Bug fixes and cleanup for ansible-test. (#45991)

* Remove unused imports.
* Clean up ConfigParser usage in ansible-test.
* Fix bare except statements in ansible-test.
* Miscellaneous cleanup from PyCharm inspections.
* Enable pylint no-self-use for ansible-test.
* Remove obsolete pylint ignores for Python 3.7.
* Fix shellcheck issuers under newer shellcheck.
* Use newer path for ansible-test.
* Fix issues in code-smell tests.

test/utils/shippable/shippable.sh

@@ -23,10 +23,10 @@ if [ -d /home/shippable/cache/ ]; then
     ls -la /home/shippable/cache/
 fi
 
-which python
+command -v python
 python -V
 
-which pip
+command -v pip
 pip --version
 pip list --disable-pip-version-check