close 74087 31.0.50
thanks

>> The only concern here is that this change might break existing users' configs.
>> The users already might have a lot of different unimaginable uses of
>> this hook such as for example to move a new tab to another position
>> on the tab-bar, etc.  Are you sure this change won't break users' configs?
>
> I'd done a search engine search using two engines for any "public" use of
> tab-bar-tab-post-open-functions and found only two cases, both of which
> would be affected positively by the patch. I'm guessing that there aren't a
> lot of people using the hook or the missing call for the initial tab would
> have cropped up sooner.

Thanks for the research.  So now this is pushed to master.