Cleanup: Remove GetFontTable from FontCache.

[PeterN]

Motivation / Problem

While cleaning up GetFontTable (it uses malloc, and passes length as return parameter) I then noticed that it is actually never called.

Presumably the code that used it no longer does.

Description

Remove GetFontTable from FontCache.

This interface is no longer used, so does not need to be implemented.

Removes manual memory management with malloc/free.

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