budget: Fix for ship, plane, land unit building abroad

budget: Fix for ship, plane, land unit building abroad

The budget command simulates an update by running selected parts of
the update code.  It skips parts that depend on hidden information
such as guerrilla warfare.  For speed, it also skips parts it doesn't
need, such as distribution and foreign sectors, ships, planes and land
units.

Skipping foreign sectors is wrong when any of the player's ships,
planes or land units will be repaired in foreign sectors, because it
makes budget use old materials and work instead of new.

Skipping foreign ships, planes and land units is wrong when they
compete with the player's for materials and work.

The bug goes back to Chainsaw's option BUDGET.  See the previous
commit for more detailed historical notes.  The update test
demonstrates it in several variations.

Fix it with the sledgehammer: don't skip foreign sectors, ships,
planes and land units.  This makes budget almost twenty times slower
in my testing.  Probably tolerable on a reasonably beefy machine, but
we can do better; the next few commits will claw back most of the lost
performance.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>