Old APU Test Pattern

[ogamespec]

The old APU revision has some irrelevant logic sitting in the Test Pattern.
We need to see what's there and add it to the section on the Wiki.

https://github.com/emu-russia/breaks/blob/master/BreakingNESWiki_DeepL/APU/test_pattern.md

[ogamespec]

See also here: https://www.nesdev.org/wiki/RP2A03_Programmable_Interval_Timer
(Research by nesdev guys)