Removed unused requires & added a new sanity check!

[SpinnySpiwal]

Added a sanity check which works for all Lua versions to prevent someone from using registerArray[1] = true; (this sadly is a real thing, I don't think it can be fixed due to the way the VM is built.)
Why does this benefit the project? It prevents anyone going into any obfuscated file and quite literally beautifying it, looking for the loop, and looking for the first index expression you see, and say the base name was T,
you'd do

while A do
    T[1]=true --> No more AntiTamper?!
end

and if UseDebug is true, all you have to do is run the file and comment out the line of the error call.

[levno-710]

It could be possible to modify Compiler:allocRegister to not always choose the first free register, but to have a set of the next n free registers and choosing one from them randomly.

Something like this:

local free_regs = {}
local next_free = 1
local free_count = 0

-- ensure at least n free registers exist
local function grow(n)
    while free_count < n do
        free_count = free_count + 1
        free_regs[free_count] = next_free
        next_free = next_free + 1
    end
end

-- allocate a register randomly from the next n free registers
function alloc(n)
    n = n or 8

    grow(n)

    local limit = math.min(n, free_count)
    local idx = math.random(limit)

    local reg = free_regs[idx]

    -- remove chosen register (swap-remove)
    free_regs[idx] = free_regs[free_count]
    free_regs[free_count] = nil
    free_count = free_count - 1

    return reg
end

-- free a register
function free(reg)
    free_count = free_count + 1
    free_regs[free_count] = reg
end