Improve detecting statement inclusion

[ostr00000]

Steps to reproduce

1. Consider following code in include_error.py:

   """Undefined variable reproduce test"""
   
   if (val := True) or (val_2 := True):
       print(val)
       print(val_2)
   else:
       print(val)
       print(val_2)
   

2. Run pylint ./include_error.py

Current behavior

No error in Pylint, but there is a runtime error.

Expected behavior

Pylint should show warning (ex. undefined-variable), because there is a possible execution path where val_2 is not defined.

python -c "from astroid import __pkginfo__; print(__pkginfo__.version)" output

• 2.15.0-dev0

Additional information

astroid incorrectly assumes statement inclusion based on statement exclusion (currently there exist only function are_exclusive).
A new function determining statement inclusion should be added. All places where function are_exclusive is used should be reviewed, and if required, a new function should be used.
Detailed information in #2023 (comment)