Support resolve_call_path resolution for same-file definitions

[charliermarsh]

If a user specifies a classmethod decorator or other setting based on a call path, we only respect that call path when the decorator is imported.

For example, if the file is foo.py, and user defines a method like:

def bar():
  ...

Then if the user lists "foo.bar" as a call path for a call path-based setting, we only respect it in files that import foo or from foo import bar etc. -- we wouldn't respect it in foo.py itself.