Version 1.2.1: Speedrun mode shop RNG fix

This is just a small update that should hopefully make life a little easier for speedrunners.

• In speedrun mode, shops now don't use RNG at all - they just cycle through items each time you visit the shop. (There's separate cycles for Clownpiece and Nitori. Things will still feel a bit random since item IDs aren't unlocked for purchase linearly but you should always get the same items in the same order every time now)