peer type resolution for [*]T and *[N]T

[andrewrk]

ir_resolve_peer_types needs another case.

test "peer types: [*]T and *[N]T" {
    var array: [8192]u8 = undefined;
    var derp: [*]const u8 = undefined;

    const T = @TypeOf(&array, derp);
    @compileLog(T);
}

The resolved type is the unknown pointer. It should additionally work if either of them is const, with the resolved type having const