checker: fix checking for option matching with non-option

[felipensp]

Fix #20663

enum Test {
    a
    b
}

fn optional() ?Test {
    return none
}

fn optional2() ?Test {
    return .a
}

fn main() {
    match optional() {
        .a { assert false }
        else { assert true }
    }

	match optional2() {
        .a { }
        else { }
    }
}

[spytheman]

Excellent work.