function invokeNode(args, done, opts = {}) {
  if (typeof args === 'function') {
    opts = done;
    done = args;
    args = [];
  }
  return createSubprocess(args, done, opts);
}
Invokes subprocess with currently-running `node`.

Useful for running certain fixtures as scripts.

@param {string[]|RawResultCallback} args - Args to `mocha` or callback
@param {RawResultCallback|Object} done - Callback or options
@param {Object} [opts] - Options
@returns {ChildProcess}