[nim] disable panics for danger

[inv2004]

It is a bit strange, but in my tests with lto the panics::on slows down the speed/danger build:

panics:on: 2054fps else: 2140fps

[shish]

Accepting for the moment, but I do wonder if there's a more sensible approach than "have a separate build script for every permutation of build flags" 🤔

[inv2004]

Sounds like, but it makes visible diff on pc, unfortunately cannot recheck on your hardware, but at least it is like expected: danger which is faster