Tetris: PAL Mode

Emulates the PAL edition of Tetris for people with NTSC cartridges.

Though this sounds absurd, it is accomplished by meticulously polling every 6/5 of an NTSC frame (which make the polling rate 60hz * 5/6 = 50hz), and updating the game state based off of that. This is in turn accomplished through the MMC3's *scanline counter* (which required a conversion of NES Tetris's mapper from MMC1).

It's still mostly untested, but the end goal is to be able to run TASes made for PAL Tetris on here without any issues, so that it may be a true alternative for people with access to only NTSC hardware.

Database match: Tetris (USA)
Database: No-Intro: Nintendo Entertainment System (v. 20210216-231042)
File SHA-1: 77747840541BFC62A28A5957692A98C550BD6B2B
File CRC32: 6D72C53A
ROM SHA-1: FD9079CB5E8479EB06D93C2AE5175BFCE871746A
ROM CRC32: 1394F57E