Namco's Speed Racer - MAME Emulation Improvements from cam900 and R.Belmont

cam900 greatly improved the video emulation for Namco's Speed Racer, which in turn exposed some logic bugs, which turned out to be issues in the Intel 80960 core. Between these fixes the game is now properly playable, which it never was before despite being marked as 'working' Like many recent MAME fixes the research done to fix these was AI assisted, with the AI both identifying how the road wrapping on the rotation should work for this game, and a static audit of MAME's Intel 960 core that exposed a few flaws, including one that caused memory corruption in the emulated system as well as a few maths related issues.