http2 - compat "socket"

[ronag]

The compat socket getter should probably have a bit more null checks in order to be compat with old code:

i.e.

  get socket() {
    return this.stream && this.stream.session && this.stream.session.socket || undefined;
  }

instead of

  get socket() {
    return this.stream.session.socket;
  }

@apapirovski

[apapirovski]

Thanks for looking into this! There is a PR (#15254) open that deals with it in a slightly different way since a lot of existing implementations also try to access a property of the socket and so returning undefined is not enough.