The `__future__` we relied on is now, where the 3 specific things are
all included [since Python 3.0](https://docs.python.org/3/library/__future__.html):
* absolute_import
* print_function
* unicode_literals
* division
These import statements are no-ops and are no longer necessary.
The categorization can be viewed by using the `-group-specializations` command
line argument.
```
% utils/analyze_code_size.py -arch arm64e -group-specializations -categorize exe
```
Add `-list-group-specializations` to see the individual functions listed
under each group.
Current groups:
Swift.stdlib class
Standard library specialization with one class type.
Swift.stdlib class(dict)
Standard library specialization of a dictionary type with a single class type.
Swift.stdlib foundation
Standard library specialization involving one foundation type (and possibly a
standard library type) or two foundation types.
Swift.stdlib foundation, class
Standard library specialization where the the first type is from the
Foundation library and the second is a class.
Swift.stdlib other
Standard library specialization with types other than the ones listed
here.
Swift.stdlib stdlib
Standard library specialization involving standard library types only.
Swift.stdlib stdlib, class
Standard library specialization where the the first type is from the
standard library and the second is a class.
Two changes:
* If a function is a function signature (or any other) specialization of a generic specialization, count it is generic specialization.
Function signature speializations are just small modifications of the original function, whereas generic specializations are real copies. So it makes more sense to "prioritize" generic specializations.
* Create a separate category of generic specializations of stdlib functions.