Micro-optimize randomFill. NFC

[sbc100]

Only use the node fallback code when its actually needed, otherwise assume that crypto.getRandomValues is available out-of-the-box (which it is on node v19 and above.

[sbc100]

Interrestingly enough it seems that the builtin crypto that comes with node v19 and above is not the same is that one you get when you require('crypto)'. Specifically crypto.randomFillSync only exists in the later!

var mycrypto = require('node:crypto');

console.log(crypto.randomFillSync);  // undefined
console.log(mycrypto.randomFillSync);  // defined!

[kripken]

Oh, I see there is automerge, so removing lgtm. but lgtm with the unneeded files removed