minecartMaxSpeed isn't capped from going into the negatives

If you try to modify the minecartMaxSpeed above 1000 the game will still behave as if it was 1000.
The same safeguard isn't present with negative values however

This allows you to encounter these things:

• maxSpeed -999999999 will crash your game due to integer overflow
• maxSpeed -99999999 will freeze your whole system due to high resource usage
• maxSpeed in lower negatives (ie. -100/-10000) will give minecrafts infinite momentum when you ride them.

Expected Behaviour

Minecraft would ignore these illegal values.