conditional expressions don't apply always true logic

```py
from typing import TYPE_CHECKING

b = 1 if TYPE_CHECKING else ""
reveal_type(b) # int | str
```

Start by reproducing the issue's Python snippet and trace how conditional expressions handle TYPE_CHECKING in the type-checking logic. Identify the relevant implementation and tests for conditional-expression inference; done means the revealed type reflects TYPE_CHECKING's always-true behavior instead of int | str.

Written by the indexing model from the issue text.