Stream async iteration doesn't work with already closed streams

[TimothyGu]

'use strict';

const { Readable } = require('stream');

const r = new Readable({
  objectMode: true,
  read() {
    this.push('asdf');
    this.push('hehe');
    this.push(null);
  }
});

(async () => {
  for await (const a of r) {
    console.log(a);
  }
  for await (const b of r) {
    console.log(b);
  }
  console.log('done');
})();

This prints

asdf
hehe

notably without the "done" line.

[TimothyGu]

/cc @mcollina @devsnek