Fixed test generation for generics

[tochilinak]

Description

Fixes #1822.

Tests for that example are still not generated, but now for completely different reason (opened issue #1845).

How to test

Manual tests

Python code with generics:

from typing import TypeVar, Generic
from logging import Logger

T = TypeVar('T', bound=bool)
U = TypeVar('U', str, object)


class LoggedVar(Generic[T]):
    def __init__(self, value: T, name: str) -> None:
        self.name = name
        self.value = value

    def set(self, new: T) -> None:
        self.value = new

    def get(self, x: U):
        return self.value, x


def func(x: T, y: U):
    if x:
        return y
    else:
        return 100

Tests are generated for all listed functions.

Self-check list

Check off the item if the statement is true. Hint: [x] is a marked item.

Please do not delete the list or its items.

• I've set the proper labels for my PR (at least, for category and component).
• PR title and description are clear and intelligible.
• I've added enough comments to my code, particularly in hard-to-understand areas.
• The functionality I've repaired, changed or added is covered with automated tests.
• Manual tests have been provided optionally.
• The documentation for the functionality I've been working on is up-to-date.