loop: add sleep between loop

[krichprollsch]

No description provided.

[krichprollsch]

I used the benchmark on my own computer to compare a release build between main and this PR:
main

$ npm run bench-puppeteer-cdp

> demo@1.0.0 bench-puppeteer-cdp
> node puppeteer/cdp.js

................................................................................
....................
total runs 100
total duration (ms) 25686
avg run duration (ms) 253
min run duration (ms) 187
max run duration (ms) 316

this PR

$ npm run bench-puppeteer-cdp

> demo@1.0.0 bench-puppeteer-cdp
> node puppeteer/cdp.js

................................................................................
....................
total runs 100
total duration (ms) 29046
avg run duration (ms) 287
min run duration (ms) 187
max run duration (ms) 332

[krichprollsch]

But we still use 3.2% of my CPU for doing nothing...