Fix 51bd344f10: Incorrect translation table used for older NewGRFs.

[PeterN]

Motivation / Problem

Incorrect logic was used to select the default translation table for older GRFs in #12646.

A litany of incorrect logic.

• Selection of climate-dependent translation table for pre-v7 GRFs was incorrectly applied to pre-v8.
• Where the use of bitnum translation table was used for pre-v7 GRFs, it incorrectly used this instead of an installed translation table.
• Forcefully installing a default translation table meant that it was not actually possible to know if the translation table was installed by the NewGRF or if it is default.

Description

No longer force-install a translation table. We don't revert back to the old ways of different logic to select cargo, we now just pick a prebuilt default translation table instead of installing it.

Pick the correct translation depending depending on context. In most cases this is:

1. The installed table
2. If pre-v7 then the climate-dependent table.
3. Otherwise the climate-independent table.

In the one place where pre-v7 force uses the bitnums, then any installed table is ignored. This might not be correct, but it is the behaviour that was used prior to #12646.

Limitations

Checklist for review

Some things are not automated, and forgotten often. This list is a reminder for the reviewers.

• The bug fix is important enough to be backported? (label: 'backport requested')
• This PR touches english.txt or translations? Check the guidelines
• This PR affects the save game format? (label 'savegame upgrade')
• This PR affects the GS/AI API? (label 'needs review: Script API')
  • ai_changelog.hpp, game_changelog.hpp need updating.
  • The compatibility wrappers (compat_*.nut) need updating.
• This PR affects the NewGRF API? (label 'needs review: NewGRF')
  • newgrf_debug_data.h may need updating.
  • PR must be added to API tracker

[PeterN]

Example of one wagon. Not exactly an exhaustive test, but one none the less.

14.1:

master:

This PR: