Wrong type inferred when "not in" narrowing Any

[JukkaL]

The revealed type here is str | None, which doesn't make sense:

from typing import Any

def f(x: Any) -> None:
    if x is not None and x not in ["x"]:
        return
    reveal_type(x)  # "str | None"

The behavior was changed in ed0cd4a. The inferred type before this commit was Any, which seems reasonable.