[tz] Lack of "initial" transitions for some zones

[Paul Eggert]

Jon Skeet wrote:
> So*if*  we wanted to change anything (and it's unclear whether we should)
> the simplest option would probably be to give an extra zone line for each
> of those zones, specifying standard time until the first transition.

Thanks for looking into it.  Since this doesn't seem to affect anybody (other 
than validation testing) I'm somewhat inclined to let sleeping dogs lie.