Adjust efficient num workers for Apple M1 Max

[maht0rz]

I was investigating proving performance on Apple M1 Max, and managed to double the proving speed by adjusting the number of threads/workers used in this config:

o1js-bindings/js/node/node-backend.js

Line 142 in c5aa5f1

'Apple M1 Max': 3,

The associated issue has apparently been fixed in newer chromium (?) and/or nodejs. So i've upgraded to nodejs v21.4.0 and set the num workers to 7, which double my proving speed for 2^16 constraints from ~50s to ~24s.

I'm unsure of all implications this has for the bindings or o1js in general, but its a significant improvement from my sparse testing.

[mitschabaude]

Nice! Let's change the config then