[Freeciv-Dev] (PR#13539) Fix AI tile effect miscalculation

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=13539 >

I see the problem now.  Since aicity hard-codes all the logic inside
generic_city_refresh it will have to hard-code this too.  But this
shouldn't be a new function in city.c it should just go straight into
aicity.c like all the other logic.

Also I wouldn't assume that calling generic_city_refresh here will be
substantially slower.  I suspect calculating the worker outputs accounts
for a substantial portion of the function's runtime, and that has to be
done anyway.  However we don't want to do a full refresh (trade routes
don't need updating) and a partial refresh isn't enough (there might be
a partial refresh already for all I know).  So a change to the interface
would be needed here to get optimal speed.

-jason