Update for loop semantics to Lua 5.4

[hugomg]

Pallene's implementation of the for loop is not equivalent to Lua's in some corner cases:

The first is when the loop step is zero:

• Lua 5.3 loops infinitely if start ≥ limit, and skips the loop if start < limit
• Pallene loops infinitely if start > limit, and skips the loop if start ≤ limit.
• Lua 5.4 raises a runtime error.

The second is when the loop variable overflows:

• In Lua 5.3 and Pallene, the internal loop variable can overflow, causing an infinite loop.
• In Lua 5.4, a loop count is computed before the start of the loop, using integer division.