Esm: private fields in node 10 with harmony flag

[neyasov]

```// test1.mjs
class A {
#x = 1

constructor(x) {
this.#x = x
}
x() {
return this.#x
}
}
`` node --harmony ./test.mjsNo errors node --harmony -r esm ./test.mjs` SyntaxError: Unexpected character '#'

[jdalton]

Hi @neyasov!

Yep, it's on my todo.

Update:

v3.0.30 is release 🎉