Fix Field(number) in snarkyjs

[mitschabaude]

Behaves wrong when number is an integer outside the int32 range. Demonstration:

Welcome to Node.js v17.7.2.
Type ".help" for more information.
> let {Field} = require('snarkyjs');
undefined
> let MAX_UINT32 = 2**31 - 1
undefined
> MAX_UINT32
2147483647
> Field(MAX_UINT32).toString()
'2147483647'
> Field(MAX_UINT32 + 1).toString()
'28948022309329048855892746252171976963363056481941560715936230020278405562369'
> 

I believe the error is caused by int32 coercion happening in Ocaml, when converting float to int in this line:

mina/src/lib/snarky_js_bindings/lib/snarky_js_bindings_lib.ml

Line 59 in 66da4ad

let value = Float.to_int value in

[mitschabaude]

closing since it's already merged into snarkyjs