loop checker is way too eager

not sure if this changed recently, but something's up with the look checker. it's way too easy to get it to kick in.

for example: https://www.khanacademy.org/computer-programming/sieve-of-eratosthenes/5571406712602624

on two machines i have tried this on it grinds to a halt complaining that 'p()' is taking too long. p itself has a single 'point()' call in it, no loops or anything else. the whole draw call takes a little longer than 1 second.

Start by reproducing the linked Sieve of Eratosthenes example and confirm whether the loop checker reports p() despite its single point() call. Trace the checker behavior that produces the timeout, then verify that this example no longer triggers a false warning while genuine long-running code is still detected.

Written by the indexing model from the issue text.