Switch away from iteration shims.
Review Request #11850 — Created Oct. 14, 2021 and submitted — Latest diff uploaded
In the Python 2 to 3 conversion, many iteration methods (such as
keys()were changed from returning lists to iterators.
In order to be correct in usage everywhere, we used
consistent behavior across versions. Now that we're Python 3+ only on
the master branch, we can get rid of these and just use the builtins.
Ran unit tests.