Both WebKit [1] and Blink [2] are raising or have raised their limits as it seems to improve their Speedometer2 performance. The spec stil limits it to 5.

[1] https://bugs.webkit.org/show_bug.cgi?id=237168
[2] https://groups.google.com/a/chromium.org/g/blink-dev/c/ncLo1AMia5I/m/BNdp42V9AQAJ

I've tried this and I couldn't see difference in speedometer numbers, at least when run in CI.
But we could still consider doing this, both in the main thread and workers.

(I have some other setTimeout(,0) simplifications in https://phabricator.services.mozilla.com/D155841, but not sure how much I like all those)

Speedometer 3 is no longer affected by this, as far as I know.