We won't raise issues when builtin names exist only on python 2 or in python 3.
To do this we need to know the exact version of python analyzed. This will be later provided by SONARPY-631 and SONARPY-677.
More concretely we will cover builtins which exist in both python 2.7 and python 3.8.
exec = 21 # False Negative. This doesn't exist in python 2.