* Add isort_code.sh to sanity tests
* Run tools/distrib/isort_code.sh
* Fine tune the import order for relative imports
* Make pylint and project generation happy
* Fix a few corner cases
* Use --check instead of --diff
* The import order impacts test result somehow
* Make isort print diff and check output at the same time
* Let tools/run_tests/python_utils be firstparty library
* Run isort against latest HEAD
* Remove Python 2.7 binary wheels
* Make sure pip won't pick-up newer versions
* Attempt to fix the distribtest
* Fallback to virtualenv==16.7.9 for 34 and 35
* Remove 34 from binary wheel distribtests