Ship modern ES targets of Ganache along side older ES versions

[davidmurdoch]

We currently publish ganache targeting node 10.7.0, but we could easily create additional builds that target more modern ES versions, which will increase performance for those versions (node 12 and 14, modern browsers, etc).

One feature in particular is ES private fields are compiled to WeakMap lookups, which is costly, as it involves a function call, map.has check, branching, and a map.get/map.set. I run a microbenchmark on this in the past and I can't remember the results, but they were significant enough to ensure we memoize private field lookups in each function call, e.g.,

function myFunction() {
  const blockchain = this.#blockchain;
  otherFunction(blockchain.thing1, blockchain.thing2);
}

instead of

function myFunction() {
  otherFunction(this.#blockchain.thing1, this.#blockchain.thing2);
}