Iterator functions for ranges perform far worse than a simple `while`

[drkameleon]

Describe the bug

Compare:

i: 0
while [i < someBigNumber][
     ; do sth with i
     inc 'i
]

with:

loop someBigNumber 'i [
    ; do sth with i
]

or:

loop 1..someBigNumber 'i [
    ; do sth with i
]

(I thought this was "solved" but, apparently, it's not?)