workaround for #2043

[Hejsil]

As mentioned here #1685 broke this code:

test "" {
    var a: usize = 0;
    x: {
        break :x &a;
    }.* = 1;
}

This PR changes translate-c to output valid code again. The way this is done, is to trick the parser into parsing an expression at stmt level instead of a labeled block:

test "" {
    var a: usize = 0;
    (x: {
        break :x &a;
    }).* = 1;
}

[ghost]

Thanks Hejsil, that got my project oxid working again